Summary of Statistical Tests

Method

Groups

Scale of Measurement

Purpose

z test

1

Interval

Test means

t test

1

Interval

Test means

  Independent groups

2

Interval

Difference between 2 means

  Dependent groups

2

Interval

Difference between 2 means

F test for variance (Scheffé)

2

Interval

Find differences between variances

ANOVA

2 or more

Interval

Differences among means

Chi square

1 or more

Nominal

Determine if observations = frequencies or if variables are associated

Correlation (Pearson r)

2

Interval

Degree of relationship

Correlation (Rank Order)

2

Ordinal

Degree of relationship

Correlation (Point Biserial)

2

X interval,
Y nominal

Degree of relationship

Correlation (Phi)

2

Nominal

Degree of relationship

(after Young & Veldman, 1981, p. 538)