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A test for comparing the means of two samples, or the mean of one sample (or even parameter estimates) with a specified value; also known as the "Student t-test" after the pseudonym of its inventor.

1 vote

Appropriate post-hoc test after repeated measures anova?

paired: yes since you have within subject measurements two way: yes since the ANOVA didn't tell you which group it was that rejected the null hypothesis of three equal groups. You might look at group …
David Ernst's user avatar
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1 vote

Apparent contradiction between t-test and 1-way ANOVA

Especially when you have only one way (therefore no interaction effects) and few groups, the ANOVA is not the only valid tool. You could do t-tests as long as you correct for multiple testing. The com …
David Ernst's user avatar
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1 vote
Accepted

Is there a paired t-test for a multiple-to-one correspondence between data sets?

You might use one line in your data-set per shuffled element in B. In the multiple A column cells corresponding to a B element, you would always put the same value. You can then make a paired test on …
David Ernst's user avatar
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1 vote
Accepted

Equivalent of two one-sided t-tests for binomial test?

Your approach is about as sensible as doing the same with another statistical distribution. There are some problems that need to be addressed. Regarding p-values, if you allocate half of your $\alpha …
David Ernst's user avatar
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1 vote

Multiple t-test and Bonferroni correction

There are two possibilities as I see it. None of them have recourse to multiple testing. Your willingness to do corrections for multiple testing shows your honesty, your intent not to do p-hacking, bu …
David Ernst's user avatar
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1 vote

Paired t-test for 3 groups

Since you do only two tests, divide the $\alpha$ level per test in two. That's a Bonferroni correction. You don't need to correct for a third possible test that doesn't interest you. No need to divide …
David Ernst's user avatar
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1 vote

t-test for non normal distribution

You don't need your sample points to be normally distributed if your sample is big enough. 30 serves as a rule of thumb. You have 1% of 700M in each group, thus twice 7M. No worries there. As you don …
David Ernst's user avatar
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0 votes

dependent or independent t test for two group

Do the latter with a Welch t test. I have never heard of a test comparing a subgroup of your data with the whole group that contains the subgroup. I'm not saying it's impossible, but at the very leas …
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1 vote

Understanding two tailed t test confidence intervals

Yes, why shouldn't it? You can always compare confidence intervals to points (like 0) You shouldn't compare confidence intervals to other confidence intervals Only one out of 20 95% confidence inter …
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1 vote

Null hypothesis of t-test and ANOVA

There is the distinction between the population mean(s) that you want to make a pronouncement about by investigating the sample mean(s) and sample variance(s). You description isn't sufficiently expli …
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-1 votes

If I have three sets of continuous data which are not normally distributed, can I still comp...

ANOVA is quite robust to violations of normality if the variances are roughly equal and the sample sizes are similar as well. Both are not given here which is a problem. You could use Welch t-tests i …
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1 vote
Accepted

Does this t.test require a lower- or upper-tail test?

This depends on how you compute the paired sample difference. before - after => greater after - before => less
David Ernst's user avatar
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3 votes
Accepted

Are we misuse the t-test in randomized experiment?

As far as normality is concerned, this can be helped by increasing the sample size to 60. To your main question: If you see the 20 people as the population to draw the two samples from, then your re …
David Ernst's user avatar
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1 vote
Accepted

Hypothesis testing - interpreting contradicting results

If your n is tiny, your test could be so under-powered that it will fail to reject all but the most ridiculous null hypotheses. edit: I see now that the standard deviations are 6 or 7 times as large …
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2 votes
Accepted

t test alternative when participants can belong to multiple groups?

There are a few possibilities. You could make it a two way ANOVA: A or notA B or notB That would also allow you to look at interaction effects. You would need to put some thought into how many an …
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