Learning Check, T-tests

1. A research article reports results of a study using a t test for dependent means as "t(16) = 2.67, p < .05." This means

a. the results were inconclusive.
b. there were 16 subjects.
c. the t score was 16.
d. the t score was 2.67.

2. Testing subjects before and after an experimental manipulation is called a __________ design.

3. A research article reports results of a study using a t test for dependent means as "t(38) = 3.11, p < .01." This means

a. the result is significant.
b. the result is not significant.
c. a one-tailed test was used.
d. the critical value for .01 alpha was 3.11.

4. Which equations have the following structure:

A deviation from a mean divided by a standard deviation?

Answers below

Answers, LC T-tests

1. d

2. repeated-measures, OR within-subjects, OR pretest-posttest

3. a

4. equation for Z-score: X - M / SD

hypothesis-test when pop variance known:

Z= X-bar - Mu / SE-means

t-test for single sample (Mu known)

t(df)= X-bar - Mu / S_M [est SE]

t-test for dependent means

t(df)= X-bar(diff) - Mu(diff) / S_M (mean diff)