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Question: <p>I have two arrangements(i.e. permutations) of numbers. First one is the target/real arrangement. Second, is the observed arrangement.</p>
<blockquote>
<p>e.g.</p>
<p>Target := 1,2,3,4,5,6,7</p>
<p>Observed := 4,1,7,3,2,5,6</p>
</blockquote>
<p>Any two elements in an arrangement is not equal. What kind of t... | https://stats.stackexchange.com/questions/79380/hypothesis-testing-for-equivalence-of-two-arrangements |
Question: <p>I am quite confused about a question that came up in my exam.</p>
<p><strong>Question:</strong> <em>The travel times on two alternative routes through a network are recorded on 20 working days during a month. The results of this are given in Table 4.
Perform an appropriate hypothesis test to investigate th... | https://stats.stackexchange.com/questions/276323/dependent-vs-independent-sample |
Question: <p>Suppose there are 24 factories who all fabricate the same product with a certain percentage of that product being faulty. We have a table of data:</p>
<p>Factory, Produced, Faulty</p>
<p>F1, 212, 31</p>
<p>F2, 1021, 145</p>
<p>…, …, …</p>
<p>F24, 480, 40</p>
<p>Now I want to check factory F1 has a differen... | https://stats.stackexchange.com/questions/473018/comparing-a-proportion-to-a-mean-proportion-which-test |
Question: <p>In multiple test we adjust the significant level by BH. I used p.adjust in R and adjust my p value after that when I print those out it has some 0 and 1, I don’t get what it means .Also, does p.adjust default 0.05 significant level? In my knowledge, BH should change the significant level instead of p value... | https://stats.stackexchange.com/questions/473580/question-about-p-adjust-in-r-and-bh-correction |
Question: <p>How can I show that the hypothesis <span class="math-container">$\mu = \mu_0$</span> is true exactly if <span class="math-container">$\mathbf a'\mu = \mathbf a'\mu_0$</span> for all vectors <span class="math-container">$\mathbf a \in \mathbb R^p$</span>?</p>
Answer: <p>Consider that <span class="math-con... | https://stats.stackexchange.com/questions/473620/how-can-i-show-that-the-hypothesis-mu-mu-0-is-true-exactly-if-mathbf-a |
Question: <p>Let's say we want to test the following hypotheses:</p>
<p><span class="math-container">$H_0: \mu = 0$</span> <span class="math-container">$H_1: \mu > 0$</span></p>
<p>for a random sample <span class="math-container">$\{X_1, \dots , X_n\}$</span> that is normally distributed <span class="math-con... | https://stats.stackexchange.com/questions/475402/what-does-it-mean-to-fail-to-reject-in-a-one-sided-hypothesis-test |
Question: <p>If my main hypothesis is that there will be no difference between two different designs in an experiment, should I be more concerned about the alpha error (rejecting H0 when it is true) or beta error (accepting H0 when it is false)?
Also, would my null hypothesis in this experiment be that there is a diffe... | https://stats.stackexchange.com/questions/475535/alpha-error-vs-beta-error |
Question: <p>I want to test a hypothesis saying 50% of employees in a company are happy. A survey of 100 people has been made and 41 say that they are happy.
My questions: I can't understand what I am given.
(1) Is the hypothesis <span class="math-container">$H_0: \mu_0 = 50$</span> <span class="math-container">$H_1:\... | https://stats.stackexchange.com/questions/476733/hypothesises-testing |
Question: <p>I'm reading <a href="https://journals.sagepub.com/doi/abs/10.1177/106591299905200309" rel="nofollow noreferrer">The Insignificance of Null Hypothesis Significance Testing</a> and on page 654, the author states that most people incorrectly think that the null hypothesis significance test produces <span clas... | https://stats.stackexchange.com/questions/487928/can-you-create-an-example-showing-when-the-p-value-pdh-0-does-not-imply-pro |
Question: <p>Assume we are testing if the true average weight of milk cartons is 100g. We may specify <span class="math-container">$H_0: \mu = 100$</span> and <span class="math-container">$H_1: \mu \ne 100$</span>.
Let's assume the true weight is 102.</p>
<p>In the course of testing we may calculate metrics, such as th... | https://stats.stackexchange.com/questions/487972/is-a-hypothesis-test-useful-if-our-null-hypothesis-is-not-the-true-value |
Question: <p>Investigating a t-Test, I ran some "experiments", generating randomly distributed values around a given mean, and running a whole bunch of t-test (always with new data) for conditions where the null-hypothesis is true, and I indeed found, that the type 1 error, the ratio of the number of times the t-test i... | https://stats.stackexchange.com/questions/225183/interdependence-of-type-1-error-and-type-2-error-in-p-value-based-hypothesis-tes |
Question: <p>Can a hypothesis test be performed if I have a non-normal population, small sample size, but population standard deviation is known? We are testing if the mean differs from the given mean.</p>
Answer: <p>The <a href="https://en.wikipedia.org/wiki/Student%27s_t-test" rel="nofollow">t-test</a> is <a href="h... | https://stats.stackexchange.com/questions/226282/hypothesis-testing-options-on-non-normal-populations |
Question: <p>I have daily return data for SPX over 50 years. And I calculate the mean return by just taking arithmetic average. I want to test the hypothesis whether the mean is 0.</p>
<p>Can I use the t statistic, which is (mean-0)/sample varirance, to test whether the mean return is 0? If not, what statistic should ... | https://stats.stackexchange.com/questions/229270/how-can-i-test-whether-the-mean-return-of-stock-indices-is-0 |
Question: <p>I'm trying to do some hypothesis testing for work, but I have to admit that it's a bit trickier when you have to formulate the question yourself.</p>
<p>I have some data of the number of errors in a software we provide in the first 3 months after going live. I also have the number of those errors that are... | https://stats.stackexchange.com/questions/230891/setting-up-hypothesis-testing-problems |
Question: <p>I have dataset about vehicles that crossed a certain singalized intersection (each record is vehicle). I want to model the relationship between the entrance time relative to the yellow onset (independent variable) and the number of vehicles (dependent variable). To this end, I use the following logistic mo... | https://stats.stackexchange.com/questions/233648/what-to-compare-means-or-variances |
Question: <p>Normally it is best to be able to set up a randomized AB test to measure if some change is actually better than the original. What about in situations where it is not ideal to AB test? </p>
<p>For example, we are a ride sharing company operating in an area where the amount of drivers are much lower than... | https://stats.stackexchange.com/questions/234213/measuring-difference-when-ab-testing-is-not-ideal |
Question: <p>I have to compare pre and post training effectiveness for group of Managers who have undergone training programme. I have data based on rank order from 1 to 4 where 1 being the most preferred and 4 being the least preferred . Based on the pre and post data i have to give the percentage improvement in the m... | https://stats.stackexchange.com/questions/234287/i-have-to-compare-pre-and-post-training-effectiveness-for-group-of-managers-stat |
Question: <p>I am in a Stats class with a brilliant Professor that I unfortunately do not get everything they say and or do. I have a question of theirs that I would like to see how others address the answer to it. The question is below. I am having trouble connecting how to decipher a Type I and a Type II and how it s... | https://stats.stackexchange.com/questions/245745/hypothesis-testing-type-i-and-type-ii-with-erroneous-error |
Question: <p>Can anyone help me out with this question? My notes & textbooks just aren't giving me the explanations I need.</p>
<p>The average household size in a certain region several years ago was 3.14 persons. A sociologist wishes to test, at the 5% level of significance, whether it is decreased now. Preform t... | https://stats.stackexchange.com/questions/245929/hypothesis-testing-of-means |
Question: <p>I was wondering how the statisticians come up with the statistical tests for hypothesis testings and the corresponding tables/distribution? Let's say Wilcoxon Rank Sum Test. Any references with concrete examples would be appreciated.</p>
Answer: | https://stats.stackexchange.com/questions/246253/design-invention-of-statistical-tests |
Question: <p>I have 2 sets of data.</p>
<p>First set is historical data and samples are taken up to a date. It has 3000 samples.</p>
<p>Second set of new samples are taken after that particular date. It has 400 samples.</p>
<p>I want to compare these two sets of data statistically.</p>
<p>Which test should I apply?... | https://stats.stackexchange.com/questions/248544/which-statistical-test-should-i-apply |
Question: <p>I have a data set of control and paired test values in which the control variability can be relatively high. I'd like to answer whether or not the the test values have increased relative to controls. Specifically, I wanted to examine the increase as a function (percentage/ratio) of the control value (i.e. ... | https://stats.stackexchange.com/questions/251393/probability-of-data-ratio-increasing |
Question: <p>I'm trying to see whether the number of salesman per customer entering the store affect the sales amount using a simple OLS regression. Which one is a better model to test the hypothesis? Can you also tell me why?</p>
<p>Model 1:sales= B1+ B2(salesman/customers entering the store). </p>
<p>Model 2:sales=... | https://stats.stackexchange.com/questions/252302/choosing-the-right-regression-model |
Question: <p>It seems to me that the alpha value is used behind both concepts. It is the cut off point where you determine whether to reject the null hypothesis or not.</p>
<p>So why are there two names for the same concept?</p>
Answer: <p>They are not the same concept. They are, however, related.</p>
<p>For a simpl... | https://stats.stackexchange.com/questions/252655/are-significance-level-and-critical-value-the-same-thing-in-hypothesis-testing |
Question: <p>It has been the standard in many machine learning journals for very many years that models should be evaluated against a test set that's identically distributed but has independently samples from training data, and authors report averages of many iterations of random train/test partitions of a full dataset... | https://stats.stackexchange.com/questions/254620/why-arent-cox-regression-models-validated-against-independent-test-sets-in-medi |
Question: <p>I have a doubt on how to interpret a result of a hypothesis test. For example, a scenario where I have an existing configuration and also a new configuration. I am trying to check if with the new configuration the program is faster.</p>
<p>The execution of the program in the existing configuration is 70.2... | https://stats.stackexchange.com/questions/255169/interpreting-hypothesis-testing-result-assuming-that-the-null-hypothesis-is-tru |
Question: <p>I want to know if my system is functional or not base on 30 trials. so what i did is, I have 1 group with 30 trials. the variable for the group is categorical success or fail.
for 30 trials, the system has 30 successes.</p>
<p>how to do the hypothesis testing? i feel like im very wrong. </p>
<p>can i... | https://stats.stackexchange.com/questions/257413/hypothesis-testing-for-this-simple-problem |
Question: <p>I have run a test on a treatment where the mean (of particular performance) after treatment is greater than that before and standard deviation has decreased. My t value is in the -22 area and I have not found a negative t value before. Should I just use the absolute value and check this agains the t-table,... | https://stats.stackexchange.com/questions/258169/negative-t-value |
Question: <p>How can I use t-test, my sample size is 368, my sample is dependent in nature as it is collected from same population over two period of time, population s.d is unknown.</p>
Answer: <p>This is a <a href="https://en.wikipedia.org/wiki/Student's_t-test#Paired_samples" rel="nofollow noreferrer">paired t-... | https://stats.stackexchange.com/questions/260270/can-we-use-t-test-for-large-sample |
Question: <p>I would like to discuss and analyze what is the best hypothesis test for this problem: </p>
<blockquote>
<p>We have data with the distance that each football player of each team runs in a match. Now we want to find two teams with the most similar pattern (by comparing any combination of teams). </p>
</b... | https://stats.stackexchange.com/questions/259126/what-is-the-right-hypothesis-test-for-this-problem |
Question: <p>the survey is for different online payment methods from which replies for which different methods they are satisfied, not satisfied , can't say.which test is to be done in this question.</p>
Answer: <p>It's not completely clear what you are trying to do, but if your dependent variable is the satisfaction ... | https://stats.stackexchange.com/questions/264122/statistical-test-for-3-response-answer-satisfied-not-satisfied-cant-say |
Question: <p>I'm a stats noob, so I don't really understand the statistic tests that the authors Ross, Greene, and House use to justify their results in their paper <a href="http://web.mit.edu/curhan/www/docs/Articles/biases/13_J_Experimental_Social_Psychology_279_%28Ross%29.pdf" rel="nofollow noreferrer">"The 'false c... | https://stats.stackexchange.com/questions/264696/understanding-statistical-hypothesis-tests-in-paper |
Question: <p>I have Type I CD protein data which consists of 27 Enzymes and 217 non-enzymes. I want to determine if there is a significant difference in the length of enzymes versus non-enzyme. What type of non-parametric test should I use if there is a huge difference between the sample size of enzymes versus non-enzy... | https://stats.stackexchange.com/questions/265360/what-kind-of-non-parametric-test-to-use-when-huge-difference-between-two-sample |
Question: <p>Assume we carry out a hypothesis test at the 5% significance level. We have an observed test statistics $t$ with calculated p-value $0.03$. Does that imply that the observation has to lie in the critical region? I mean $3\%$ of the distribution is at least as extreme and the critical region is the most ext... | https://stats.stackexchange.com/questions/265584/if-p-text-value-alpha-does-the-observed-test-statistic-always-belongs-to-cr |
Question: <p>I'm currently conducting a research in linguistics. The goal is to show the audience preference when it comes to different translation strategies in subtitling. The experiment design has one independent variable with two levels (2 different translations of the same clip), and the dependent variable is the ... | https://stats.stackexchange.com/questions/267033/which-test-to-use-for-generalizations |
Question: <p>so I'm new to statistics and am not very comfortable with it yet. It may be a very simple question, but I'm finding this very difficult to understand
In research papers the hypotheses are mostly in a particular direction.
Like "satisfaction is positively related to customer retention"
If this particular h... | https://stats.stackexchange.com/questions/188433/hypotheses-testing |
Question: <p>I have daily returns on S(USD/AUD). Now how to test whether average return of last 30 days is significantly different from zero at 5% level of significance ?</p>
Answer: <p>You may be looking for a so-called "HAC"-test, a "heteroskedasticity and autocorrelation consistent" test for $\mu=\mu_0$:
$$
t_{HAC}... | https://stats.stackexchange.com/questions/188948/how-to-test-whether-the-average-return-on-susd-aud-of-the-last-30-days-is-sign |
Question: <p>What statistical test would I use to compare differences in mortality among 5 independent groups? I know chi square can be used for comparing 2 groups.</p>
Answer: <p>You want to see whether the distribution in frequencies among the five groups is consistent with a discrete uniform distribution (null hypo... | https://stats.stackexchange.com/questions/189639/how-to-compare-mortality-rates-among-5-groups |
Question: <p>Suppose I have $N$ urns, each containing various mixes of red and green balls.
A subject is to make a random selection without replacement of $M$ balls from each of the urns, whereupon a count is made of the red and green for that urn, resulting in a count of these for each urn.</p>
<p>The hypothesis is t... | https://stats.stackexchange.com/questions/193301/proper-way-to-test-hypothesis-of-random-selection |
Question: <p>In practice, how do you find the uniformly most powerful test? Would you essentially brute-force all possible hypothesis tests?</p>
<p>Could we prove that there exists a uniformly most powerful test and the one that we are using is sub-optimal?</p>
Answer: <p>For a case of testing simple hypothese, there... | https://stats.stackexchange.com/questions/199027/how-to-determine-uniformly-most-powerful-test |
Question: <p>Why P value of a 2 tailed test is multiplied by 2 [=2 X P(Z>tcal)? I am looking for a answer which may explain the underlying reason except the answer 'because it is a two tailed test'. Why we also consider the opposite signed value of test statistic in two tailed test to calculate P value?</p>
Answer: <b... | https://stats.stackexchange.com/questions/200768/why-we-also-consider-the-opposite-signed-value-of-test-statistic-in-two-tailed-t |
Question: <p>Is the choice of test statistic in hypothesis testing a completely philosophical one? In other words, is the choice of test statistic and rejection/acceptance region a completely judgement call and is not bounded by any requirment?</p>
Answer: <p>I am assuming that you are asking about the choice of test ... | https://stats.stackexchange.com/questions/203868/is-the-choice-of-test-statistics-in-hypothesis-testing-a-completely-philosophica |
Question: <p>I have a dataset, <code>data</code>, that contains <code>user</code>, <code>game_played</code>, <code>amount_spent</code> and <code>amount_won</code>. So <code>head(data)</code> gives</p>
<pre><code>user game amount_spent amount_won
14 4 186 120
14 2 200 80
10 2 ... | https://stats.stackexchange.com/questions/204690/to-use-the-right-model-and-analysis |
Question: <p>I've been reading around about hypothesis testing. I don't understand why the following one sided tests are equivalent:</p>
<p>$H_0:\mu \leq \mu_0$; $H_a:\mu > \mu_0$</p>
<p>and</p>
<p>$H_0:\mu = \mu_0$; $H_a:\mu > \mu_0$</p>
<p>Any thoughts?</p>
<p>Edit:
I think I understand why they are equiva... | https://stats.stackexchange.com/questions/205958/one-sided-null-hypothesis-2-interpretations |
Question: <p>A system produces samples. I have historical data as thousands of samples. I know the number of samples, their mean and their standard deviation. This data was collected by using the same system.</p>
<p>But recently the system was modified. And I have around 30 new samples after the system update. I know ... | https://stats.stackexchange.com/questions/206240/which-hypothesis-test-should-i-apply-in-this-case |
Question: <p>Can someone explain in simple words and with many good down-to-earth examples what is the p-value and how do we find it? </p>
<p>Is it true that it shows what is the probability that the sample we have tested is true not simply by chance? Isn't that the point of the alpha level to guarantee that for an in... | https://stats.stackexchange.com/questions/205653/what-is-p-value-in-simple-words-and-good-non-mathematical-examples |
Question: <p>What is the most suitable null and alternative hypothesis for following problem? </p>
<blockquote>
<p>It is believed that the average level of Prothrombin in a normal
population s 20 mg/100 ml of blood plasma with a standard deviation
of 4 mg /100 ml. To verify this, a sample is taken from 40
indi... | https://stats.stackexchange.com/questions/208622/hypothesis-test-determine-null-and-alternative |
Question: <p>I have a large sample of 800 participants who completed a measure of relationship at 2 time points. The result of a paired-samples t-test indicates that there was no statistically significant difference between both time points. I then split the group into high risk and low risk subsets of participants lik... | https://stats.stackexchange.com/questions/213652/comparing-difference-between-two-subsets |
Question: <p>I'm not sure what the null hypothesis for this would be/ what the correct symbols are.
the data is unpaired and I'm needing to find if there evidence ( at 5% level of significance) that one thing is dependant on another. </p>
<p>for example, is there evidence that the size of the banana is dependant on th... | https://stats.stackexchange.com/questions/215070/a-hypothesis-test-for-evidence-that-one-thing-is-dependant-on-another |
Question: <p>I'm having trouble with a basic hypothesis testing question that I just thought of. The question is the following: suppose you know that a certain lawnmower manufacturing company (called Company A) makes lawnmowers that run on average 300 minutes before running out of gas with a standard deviation of 30 mi... | https://stats.stackexchange.com/questions/220246/basic-hypothesis-testing |
Question: <p>There is one chemical for plants; in absence of it (control) all 3 of them live. In presence 5 of 6 die, only 1 lives. So how can we show if it is significant or not? It may be basic but I appreciate your help. </p>
Answer: <p>I suggest to use the Fisher's Exact test in order to test if there is a statist... | https://stats.stackexchange.com/questions/144265/what-is-appropriate-statistical-test-for-one-condition |
Question: <p>I heard from the grapevine that when somebody has statistics, some tests may indicate one type of significance, while others do not. The tests themselves may be inconsistent. My question is, what is the fundamental problem that causes the tests to break down? </p>
<p>My answer, which I am not sure if corr... | https://stats.stackexchange.com/questions/145803/why-do-different-statistical-tests-differ |
Question: <p>assume I know a theoretical distribution that is quite non-normal.</p>
<p>I simulate many (N) samples of given size (T).</p>
<p>Then for each sample I test if the sample average is equal to the theoretical one (t-test).</p>
<p>Then I look at the frequency of rejections as a function of T.</p>
<p>Let T*... | https://stats.stackexchange.com/questions/145286/interpretation-of-empirical-frequency-of-null-hypothesis-rejections |
Question: <p>In hypothesis testing a hypothesis is generally defined to be "a statement about the value of a population parameter". For example the mean value of the height of people living in a certain city.</p>
<p>I do not understand how this applies to the classical example of coin tossing. In coin tossing we test ... | https://stats.stackexchange.com/questions/145293/a-basic-question-on-hypothesis-testing |
Question: <p>Given two lists of characters. For example </p>
<p>List #1</p>
<p>A
C
O
P</p>
<p>List #2</p>
<p>A
O
R
T</p>
<p>How would you test whether the two lists differ significantly or not. I feel like a t-test can be applied, but I'm not sure how given I have character values as opposed to numerical values (i... | https://stats.stackexchange.com/questions/146175/would-a-t-test-apply-statistical-test-suggestion |
Question: <p>I have data in the following form:</p>
<pre><code>subject PercA PercB PercC PercD
A1 0.12 0.33 0.40 0.15
A2 0.14 0.31 0.38 0.17
...
B1 0.18 0.30 0.35 0.17
B2 0.17 0.29 0.39 0.15
...
</code></pre>
<p>The percentages in each row sum up to 1 because the perc... | https://stats.stackexchange.com/questions/146479/which-test-to-use-to-compare-calculated-percentages |
Question: <p>I have a contingency table that looks like this:</p>
<pre><code> Disease Not Disease
Exposed 372 870
Not Exposed 0 23
</code></pre>
<p>What methods would I use to estimate if there is a statistically significant difference between the e... | https://stats.stackexchange.com/questions/148406/how-to-estimate-relative-risk-for-a-small-group-which-has-0-members-with-the-out |
Question: <p>I have a sample of 40 data, that shows the average of time a person waits in a gas station line.</p>
<p>Descriptive statistics of this sample are as follow:
N= 40, mean= 115sec, std.dev.=11sec, min=90sec, max=147sec.</p>
<p>I decided to test the following hypothesis:
H0: waiting time = 115sec
H1: waiting... | https://stats.stackexchange.com/questions/148562/testing-hypothesis |
Question: <p>I have one set of data. I have two procedures for making 1-10 ranking of the data (one was used previously and one is a new procedure). I want to do a hypothesis test to see if the ranking is the same or not.</p>
Answer: <p>I would advise you to have a look at one of the follow tests:</p>
<ul>
<li>Wilco... | https://stats.stackexchange.com/questions/149089/test-two-1-10-ranking-processes-on-same-data-and-test-for-statistical-significan |
Question: <p>If we want to test whether the sample mean is at least 5 meters, how should we state the null hypothesis and alternative hypothesis? Here is what I think:
H0: µ>=5
H1: µ<5
But when determining the p value, I will be looking at a left tail probability isn't it? It just feels weird. So is my H0 and H1 cor... | https://stats.stackexchange.com/questions/152928/hypothesis-test-null-hypothesis-equality |
Question: <p>Suppose I have subjects sort 10 images into the categories "Group A" or "Group B". I want the null hypothesis to be that subjects are randomly assigning the images, and the alternate hypothesis that certain images tend to be assigned to certain categories. Importantly, I do not have an a priori hypothesis ... | https://stats.stackexchange.com/questions/153877/test-that-a-group-of-probabilities-is-different-from-chance-in-either-directio |
Question: <p>Suppose I know that the true population proportion of a mutation is p = 0.3493119. I want to know that given power = 0.8, what's the proportion of of mutation in my sample of n = 30? Here's what I have so far: </p>
<p>1 - cdf((x-p)/sqrt(p*(1-p)/30) = 0.8
Since p = 0.3493119, I can solve for x and I get x ... | https://stats.stackexchange.com/questions/157296/is-power-always-associated-with-hypothesis-testing |
Question: <p>An industrial process is in place that increases the strength of a metal component. We are tuning a couple of settings on the system to optimize the strength. There are already some settings in place, but I have found some new settings that I would like to make a recommendation to change the system to. The... | https://stats.stackexchange.com/questions/163543/hypothesis-test-one-sample-vs-two-sample |
Question: <p>I am going to measure the performance of this year. The average of the past year records (e.g. 5 years) and this year record will be used to judge how many standard deviation it is and if this year performance has improved or not. However, I have a doubt if the average should also include this year record ... | https://stats.stackexchange.com/questions/164740/measure-the-performance-of-this-year |
Question: <p>I'm trying to predict my DV based on IV (predictor variable) scores.
I have a sample size of 62.
DV is categorical (addicted or not addicted).
8 IVs are all continuous (at a push I can lose 3 IVs)
I only have access to SPSS.
Could you help me decide, please, the most appropriate and correct statistical ana... | https://stats.stackexchange.com/questions/166375/which-type-of-analysis-to-use |
Question: <p>A and B are some statements such that A implies B. I test the null hypothesis that A is true. If my test fails to reject A, does that result say anything about B? Analogously, if instead I test the null hypothesis that B is true, and my test rejects B, can I conclude that A is rejected as well?</p>
Answer... | https://stats.stackexchange.com/questions/166934/consequences-of-rejected-accepted-hypothesis |
Question: <p>Let's say we did an A/B testing, and the click rate for 1 group was 0.4 and for the other group, it was 0.3.</p>
<p>How can we go about testing whether this difference is statistically significant?
I'm thinking getting a p-value from t-test, but what would the null and alternative hypothesis be?</p>
Answ... | https://stats.stackexchange.com/questions/174787/test-if-the-difference-is-statistically-significant-in-a-b-test |
Question: <p>I have two groups of people.<br>
Group one with 16 choosing 1 and 33 choosing 2.<br>
Group two with 10 choosing 1 and 49 choosing 2.<br>
I assume they both follows Binomial distribution. So how can I found out if they are significant different from each other?<br>
(I have used nonparametric method to see t... | https://stats.stackexchange.com/questions/179148/test-if-two-binomial-distribution-are-significantly-different |
Question: <p>$$H_0:\mu=0 \quad\quad H_1:\mu>0 $$
we assume the distribution of the sample is Gaussian.<br>
If $p$-value is very big, sample mean very small, we still accept null hypothesis.<br>
Isn't it counterintuitive? Why are we still using it?</p>
<p>E.g. $x_1,x_2,\ldots,x_n$, sample mean is $-5$, variance i... | https://stats.stackexchange.com/questions/177792/p-value-in-one-sided-test |
Question: <p>I have a survey with a list of questions in which respondents can pick their perceived personality traits. Then I have a question that asks respondents about their favorite in-game character's perceived personality and a question that asks respondents about their least favorite in-game character's perceive... | https://stats.stackexchange.com/questions/56435/what-test-should-i-use-for-hypothesis-with-many-variables |
Question: <p>When varying the significance level, the rejection regions can be chosen to be nested or not nested. I was wondering what some theoretical and practical considerations are in using either nested or non-nested rejection regions? Thanks and regards!</p>
Answer: <p>It is not quite true that the rejection re... | https://stats.stackexchange.com/questions/59122/rejection-regions-nested-or-not |
Question: <p>I need to have one understanding on statistical hypothesis testing. In a typical hypothesis test, we have 2 opposite hypotheses; namely Null and Alternative. Here my textbook says that "those 2 hypotheses are not symmetrical in the sense that if we swap the hypotheses then the result will alter".</p>
<p>H... | https://stats.stackexchange.com/questions/21967/seeking-to-understand-asymmetry-in-hypothesis-testing |
Question: <p>Is a standard test applicable for situations involving exponential growth? I don't have a 'problem on my desk' that I need to solve. This is just a curiosity. Examples might include mitosis of bacteria or compounding interest for an investment.</p>
<p>In this context, we would have panel data for two diffe... | https://stats.stackexchange.com/questions/649267/hypothesis-tests-for-exponential-growth |
Question: <p>I conducted an A/B test where the treatment involved offering discounts to customers. However, after the test concluded, I discovered that the discount was not consistently displayed to customers in the test group due to an additional logic layer that determined whether the discount was significant enough ... | https://stats.stackexchange.com/questions/659770/evaluating-total-effect-on-population-after-conducting-a-b-test |
Question: <p>I am curious about a claim made in Wikipedia's article on <a href="https://en.wikipedia.org/wiki/Effect_size#Relationship_to_test_statistics" rel="noreferrer">effect size</a>.
Specifically:</p>
<blockquote>
<p>[...] a non-null statistical comparison will always show a statistically
significant results... | https://stats.stackexchange.com/questions/323862/given-big-enough-sample-size-a-test-will-always-show-significant-result-unless |
Question: <p>I'm trying to compare two samples from multivariate normal distributions to see if their distributions are equivalent (within a factor of epsilon).</p>
<p>The standard version of this test is the <a href="http://en.wikipedia.org/wiki/Energy_distance#Testing_for_equal_distributions" rel="nofollow">energy t... | https://stats.stackexchange.com/questions/55298/equivalence-test-for-two-multivariate-normal-distributions |
Question: <p>I understand it's reasonable only to not reject the null hypothesis. But why can we accept the alternative hypothesis?</p>
<p>What's the difference?</p>
Answer: <p>I'll start with a quote for context and to point to a helpful resource that might have an answer for the OP. It's from V. Amrhein, S. Greenlan... | https://stats.stackexchange.com/questions/587383/why-cant-we-accept-the-null-hypothesis-but-we-can-accept-the-alternative-hypot |
Question: <p>Suppose we have an estimator <span class="math-container">$\hat\mu$</span> of population parameter <span class="math-container">$\mu$</span> and we know that</p>
<p><span class="math-container">$$\sqrt{N}(\hat\mu-\mu)\overset{d}{\to}N(0,1).$$</span></p>
<p>We are interested in the following hypothesis sche... | https://stats.stackexchange.com/questions/627209/why-the-probability-of-rejecting-the-null-hypothesis-tends-to-1-in-this-case |
Question: <p>In hypothesis testing, alternative hypothesis doesn't have to be the opposite of null hypothesis. For example, for $H_0: \mu=0$, $H_a$ is allowed to be $\mu>1$, or $\mu=1$. My question: <em>Why is this allowed</em>? What if in reality, $\mu=-1$ or $\mu=2$, in which case if one applies, say, likelihood r... | https://stats.stackexchange.com/questions/365604/what-if-both-null-hypothesis-and-alternative-hypothesis-are-wrong |
Question: <p>When we do testing we end up with two outcomes.</p>
<p>1) We reject null hypothesis</p>
<p>2) We fail to reject null hypothesis. </p>
<p>We do not talk about accepting alternative hypotheses. If we do not talk about accepting alternative hypothesis, why do we need to have alternative hypothesis at all? ... | https://stats.stackexchange.com/questions/386982/why-do-we-need-alternative-hypothesis |
Question: <p>For a Z test, in say a Normal Z test with known variance, what is the difference between rejection areas being represented by</p>
<p><span class="math-container">$P(|Z|\geq z)$</span></p>
<p>versus</p>
<p><span class="math-container">$P(|Z|\geq |z|)$</span></p>
<p>For <span class="math-container">$P(|Z|\ge... | https://stats.stackexchange.com/questions/549552/what-is-the-difference-between-a-hypothesis-test-of-pz-geq-z-versus-pz |
Question: <p>In hypothesis testing, we set up a rejection area for rejecting <span class="math-container">$H_0$</span> in favor of <span class="math-container">$H_1$</span> with <span class="math-container">$\alpha$</span>. I don't understand why type I error (rejecting <span class="math-container">$H_0$</span>, when <... | https://stats.stackexchange.com/questions/561321/why-type-i-error-rate-is-rejection-area-in-hypothesis-testing |
Question: <p>From <a href="https://stats.stackexchange.com/a/2519/1005">a reply by John</a></p>
<blockquote>
<p>What is true is that trivially small effects can be found with very large sample sizes. That does not suggest that you shouldn't have such large sample sizes. What it means is that the way you interpret yo... | https://stats.stackexchange.com/questions/67676/is-a-test-with-small-effect-size-and-high-sensitivity-meaningful-or-useful |
Question: <p>I am hoping to understand best way to test statistical significance between 2 dependent population groups. </p>
<p>For example, consider a usability test. When 100 subjects were tested, 50 of them clicked (=50% click rate). However, 50 of the subjects were male, 40 of whom clicked for an 80% click rate fo... | https://stats.stackexchange.com/questions/69259/statistical-significance-dependent-populations |
Question: <p>I'm currently a fourth year university student. As part of my studies, I'm taking a class called Capstone, where students design and carry out a research project. An essential part of formulating this research is choosing a statistical procedure with which to analyze and present your results.</p>
<p>My st... | https://stats.stackexchange.com/questions/74684/what-statistic-procedure-to-use-for-analyzing-my-data |
Question: <p>I have the following observations</p>
<p>Oberservation ; Count </p>
<p>-1.67 ; 726 </p>
<p>18.33 ; 33</p>
<p>148.33 ; 15</p>
<p>This is obviusly not normal distributed :S</p>
<p>How can I make a test for $H_0: \mu = 0$ or even better is it possible to make a confidence interval for the mean?</p>
Ans... | https://stats.stackexchange.com/questions/79653/testing-on-non-normal-distributed-discrete-values |
Question: <p>I am trying to do a small case study in 24 hours + change.</p>
<p>For a dataset, I'm using <a href="http://ghtorrent.org" rel="nofollow">GHTorrent.org</a>.</p>
<p>A general assumption about virtual work is that richer media leads to greater productivity. I have decided to focus on <a href="http://github.... | https://stats.stackexchange.com/questions/79957/am-i-doing-my-quantitative-study-on-github-right |
Question: <p>Suppose I roll a six-sided die 1000 times and write down the number of times each face comes up. How do I test whether the die is fair? Can I use a chi-squared test where the expected number of each face is 1000/6=167?</p>
<p>There also appears to be a <a href="http://en.wikipedia.org/wiki/Multinomial_t... | https://stats.stackexchange.com/questions/80555/statistical-test-for-a-random-die-roll |
Question: <p>I'm trying to test whether or not it's true that people of similar heights tend to marry each other, and I'm a bit confused how exactly to go about it.</p>
<p>I have a data set with 96 pairs of the heights of husband and wife, so I thought I could just take the mean of the differences in height between hu... | https://stats.stackexchange.com/questions/82752/simple-question-about-hypothesis-testing |
Question: <p>I am writing a research paper where I am using an hypothesis test.</p>
<p>Is it better to give a p-value for this test or use a 5% two-tailed rejection region?</p>
<p>Thanks in advance!</p>
Answer: <p>In situations like these - it's best to look at things from the reader's perspective. Would the reader ... | https://stats.stackexchange.com/questions/82754/rejection-region-or-p-value |
Question: <p>How can you determine the direction of the test by looking at a pair of hypotheses? How can you tell which direction (or no direction) to make the hypothesis by looking at the problem statement (research question)?</p>
Answer: <p>Since we test assuming that the null is true, the null has to include a way ... | https://stats.stackexchange.com/questions/88200/how-can-i-determine-which-of-two-complementary-hypotheses-should-be-the-null |
Question: <p>I am designing my study, but I am a little stuck in which test I eventually should use. I have a between-subject design with 6 conditions (let's say A, B, C, D, E, F), with each having 6 responses (let's call these a, b, c, d, e, f), on a 7-point scale:</p>
<pre><code>IV (condition) -> DV
A -> a, b,... | https://stats.stackexchange.com/questions/90339/which-statistical-test |
Question: <p>Suppose I have a sample $\{(x_{1i}, x_{2i}, \dots, x_{mi}), i=1,\dots, n\}$of $m$ unknown random variables $X_1, X_2,\dots, X_m$. </p>
<p>How can I test if $X_1 = X_2 =\dots = X_m$?</p>
<p>Furthermore, if there is a nonrandom explanatory variable $Y$ such that $Y=y_j$ for $X_j, j=1, \dots, m$, how can I ... | https://stats.stackexchange.com/questions/90859/how-to-do-this-test |
Question: <p>I'm new to stats and I need some help. Can anybody tell me, in the most "beginner friendly" way, how to perform hypothesis testing with a geometric distribution for 2 samples?
please take into account that, until a month ago, Statistics for me was mean, mode and std dev... </p>
Answer: <p>I'm going to ass... | https://stats.stackexchange.com/questions/93244/hypothesis-testing-with-the-geometric-distribution-for-dummies |
Question: <p>I am designing a study for my project.
I wanted to test if music affects reading comprehension. This study will be a between group design. The independent variable is type of music and the dependent variable is the score on a reading comprehension task. </p>
<p>Half of participants will be randomly assig... | https://stats.stackexchange.com/questions/95235/what-kind-of-test-should-i-use |
Question: <p>I have 3 replicas for a value in different individuals. Each of these values are ratios $ab$, and $a$ and $b$ are means from $n=20$ sample pool each. Thus there are 3 times each ratio $ab$ for each individual. When comparing for differences is student t-test correct?</p>
<pre><code> 1st sa... | https://stats.stackexchange.com/questions/95431/proper-statistical-test-to-check-differences |
Question: <p>lets say I have the mean of two different measurements of something, a and b. I also have the standard deviation on a, and b, but I do not have access to all the individual measurements of a and b. Is it possible to compare the two values to see if the means are statistically different (i.e., reject the nu... | https://stats.stackexchange.com/questions/95963/how-to-compare-two-samples-without-knowledge-of-the-distribution |
Question: <p>To put it simply, I have the courses students have taken and scores on an exam. The students come from different course backgrounds. (Some have taken only course A some only D some A and D some A and B some B C and D etc etc)</p>
<p>What can test can I use to account for this?</p>
Answer: <p>You want to ... | https://stats.stackexchange.com/questions/96381/what-test-should-i-use-to-see-correlations-between-overlapping-groups-and-a-scor |
Question: <p>I have $n_X$ observations of variable X, $n_Y$ of variable Y, and $n_Z$ of variable Z. I'd like to test the hypothesis that the true mean of $X$ is equal to the sum of the means of Y and Z.
$$H_0: \mu_X - (\mu_Y+\mu_Z) = 0$$</p>
<p><strong>Initial thoughts</strong></p>
<p>I can use the sample means to ... | https://stats.stackexchange.com/questions/96803/hypothesis-testing-for-non-linearity |
Question: <p>I have a simulated distribution with mean 12.53% and standard deviation 11.83%. The sample size is big enough (10,000) to assume it is a Normal distribution. </p>
<p>How do I properly test if the value "26.05%" is significantly larger than the mean 12.53%?
Can anyone please help me to write the null hypo... | https://stats.stackexchange.com/questions/99803/is-a-data-point-significantly-larger-than-a-certain-distribution-average |
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