Suggest one psychological research question that could be answered by each of the following types of statistical tests: •z test
•t test for independent samples, and
•t test for dependent samples
Usually you use z-tests when sample sizes are large (n is greater than
or equal to 30) whether or not you know the population standard deviation.
If you do not know the population standard deviation and have a small
sample (n < 30), then you can use t-tests.
T-tests for independent samples uses two different sets of research subjects. T-tests for dependent samples uses the same research subjects in two different conditions (like a "before" condition and an "after" condition) or when there are two samples that have been matched or "paired" in some way.
You can find examples of these types of tests online or in any statistics textbook.