1. What is the symbol for pooled variance?

a. s b. s2 c. s(M1-M2) d. s2/p

2. For the independent-measures t test, which of the following describes the pooled variance?

a. An estimate of the standard distance between the difference in sample means (M? - M?) and the difference in the corresponding population means (?? - ??)

b. The difference between the standard deviations of the two samples

c. The variance across all the data values when both samples are pooled together

d. A weighted average of the two sample variances (weighted by the sample sizes)

3. What is the symbol for estimated standard error of the difference in sample means?

a. s b. s2 c. s(M1-M2) d. s2/p

4. For the independent-measures t test, which of the following describes the estimated standard error of the difference in sample means?

a. A weighted average of the two sample variances (weighted by the sample sizes)

b. The difference between the standard deviations of the two samples

c. An estimate of the standard distance between the difference in sample means (M? - M?) and the difference in the corresponding population means (?? - ??)

d. The variance across all the data values when both samples are pooled together

5. In calculating _1_, you typically first need to calculate _2_ . _3_ is the value used in the denominator of the t statistic for the independent-measures t test.

1a) s(M1-M2) b) s2/p

2a) s(M1-M2) b) s2/p

3a) s(M1-M2) b) s2/p

Suppose you conduct a study using an independent-measures research design, and you intend to use the independent-measures t test to test whether the means of the two independent populations are the same. The following is a table of the information you gather. Fill in any missing values.

Sample Size Degrees of Freedom Sample Mean Standard Deviation Sums of Squares Sample 1 n = 21 M. = 27.6 S, = 4.5 Sample 2 n, = 11 M, = 21.5 SS, = 302.5