What's the T?: The no-nonsense guide to all things trans and/or non-binary for teens

Product Information

If you are studying one group, use a paired t-test to compare the group mean over time or after an intervention, or use a one-sample t-test to compare the group mean to a standard value. If you are studying two groups, use a two-sample t-test. If you want to know whether one population mean is greater than or less than the other, perform a one-tailed t test.

A statement of the alternative hypothesis ( H a). In this test, the H a is that the difference is not 0. You don’t care about the direction of the difference, only whether there is a difference, so you choose to use a two-tailed t test.

If you only care whether the two populations are different from one another, perform a two-tailed t test.

The 95% confidence interval. This is the range of numbers within which the true difference in means will be 95% of the time. This can be changed from 95% if you want a larger or smaller interval, but 95% is very commonly used. In our example, you would report the results like this: The difference in petal length between iris species 1 ( M = 1.46; SD = 0.206) and iris species 2 ( M = 5.54; SD = 0.569) was significant ( t (30) = −33.7190; p< 2.2e-16). Other interesting articles have a similar amount of variance within each group being compared (a.k.a. homogeneity of variance)Once you're up to motorway speeds, you'll find that the T-Roc does a fine job of isolating you from road and wind noise – better than all its rivals, as it happens – so if you value calm and relaxing progress, you'll like the T-Roc a lot. Driving overview Have a human editor polish your writing to ensure your arguments are judged on merit, not grammar errors.