PSYC*1010 Chapter 10: t Tests for Two Independent Samples

Question 1

When are independent-measures t tests conducted?

Answer 1

When two sets of data from completely separate groups are being collected and compared

Question 2

How are samples differentiated in an independent-measures t-test?

Answer 2

With the subscript 1 or 2

Question 3

What does the hypothesis test for an independent-measures design evaluate?

Answer 3

The statistical significance of the mean difference between two separate groups of participants

Question 4

In an independent-measures t-test, what is population mean always set to?

Answer 4

Zero

Question 5

What does estimated standard error measure in an independent-measures t-test?

Answer 5

Measures the amount of error expected (standard distance) when the sample mean difference is used to represent a population mean difference

Question 6

What is pooled variance?

Answer 6

A single measure of sample variance that is obtained by averaging two sample variances

Question 7

When is pooled variance used to compute estimated standard error?

Answer 7

When sample sizes are unequal

Question 8

What are the three assumptions that must be satisfied before doing an independent-measures t-test?

Answer 8

• Observations within each sample are independent of each other
• The two populations from which the samples were selected are normal (or have an n>30)
• The two populations from which the samples are selected must have homogeneity of variance

Question 9

What is homogeneity of variance?

Answer 9

An assumption that the two populations from which the samples were selected have equal variances

Question 10

When is the homogeneity of variance assumption most important?

Answer 10

When there is a large discrepancy between sample sizes