8 апр. 2018 г. · When a p-value is low enough, i.e. lower than 0.05, researchers will often call it "significant". If the p-value is not low enough (p>0.05), ...

1 авг. 2020 г. · The pooled two-sample t-test must be used only when you 'know' that the two populations have equal variances.

3 янв. 2011 г. · (2) Use a two-sided test when a change of average in either direction (greater or lesser) is possible. Otherwise, when you are testing only for ...

24 нояб. 2017 г. · I am trying to interpret what it means when you have either -Inf or Inf in the confidence interval. Not because the alternative is less or greater or two.sided.

7 авг. 2020 г. · If data in the two groups are approximately normal, then a Welch two-sample t test with the sample sizes n1 and n2 will not be spoiled by ...

27 янв. 2021 г. · More generally, the denominator of the t-test in the code is an estimate of the denominator in a population version rather than an estimate of ...

13 июн. 2012 г. · You can write your own function based on what we know about the mechanics of the two-sample t-test. For example, this will do the job.

2 дек. 2018 г. · The Welch T test is a special kind of two sample T test that does not assume equality of variance between the groups. However, it is still a two ...

24 мар. 2019 г. · The degrees of freedom ν in a Welch 2-sample t test depends on sample sizes n1 and n2 and sample variances S21 and S22, as shown in your ...

19 июн. 2019 г. · The R function power.t.test does power calculations (outputs power, sample size, effect size, or whichever parameter you leave out) for t-tests.