# Power of T-Tests

What is the power of each of the following studies, using a t test for dependent means (based on the .05 significance level)?

Answer by using the examples below:

Study Effect Size N Tails

(a) Small 20 One

(b) Medium 20 One

(c) Medium 30 One

(d) Medium 30 Two

(e) Large 30 Two

https://brainmass.com/statistics/statistical-power/power-of-t-tests-408867

#### Solution Preview

See attached files.

FYI: A t-test for dependent means is also called a paired t-test.

For a formula to calculate the power of a t-test, see the following:

http://www.sjsu.edu/faculty/gerstman/StatPrimer/sampsize.PDF (3rd page)

For a discussion of the things that affect power, see:

http://www.power-analysis.com/power_analysis.htm (keep clicking next for more topics)

Here are ...

$2.19