T-Tests

Question 1

Independent Samples T-test

Answer 1

Compares two different groups
-People are in two different groups with two different conditions

Question 2

Independent Samples Null Hypothesis

Answer 2

The same means of the two groups are the same

Question 3

Assumptions of a Independent Samples T-test

Answer 3

Formal:
-Groups are independent of each other
-The distribution of the sample means for each population is normal
-Homogeneity of Variance

Informal:
-No big outliers
-Sample sizes of each group is equal

Question 4

Degrees of Freedom for Independent Samples

Answer 4

N-2

Why?: Population - # of Groups

Question 5

Dependent Samples T-test

Answer 5

Compares the same group over multiple assessments

Question 6

Dependent Samples Null Hypothesis

Answer 6

The population of difference scores is zero

Question 7

Assumptions of a dependent samples T-test

Answer 7

Formal:
-The same group is tested twice
-Sampling distribution of difference scores is normal

Informal:
There are no outliers

Question 8

Degrees of Freedom for Dependent Samples

Answer 8

N-1

Why?: Population - # of Groups

Question 9

What effect size to use for both?

Answer 9

Cohens d
-How many standard deviations the scores differ from each other