1.

A researcher wants to assess if the average age when women first marry has increased from 2000 to 2020. Let 1 = average age of first marriage for women in 2020 and 2 = average age of first marriage for women in 2000. A random sample of 10 women married in 2020 showed an average age at marriage of 24.95 years, with a sample standard deviation of 2 years. A random sample of 20 women married in 2000 showed an average age at marriage of 23.1 years, with a sample standard deviation of 1.5 years.

What are the appropriate null and alternative hypotheses?

Select one:

a. H0: 1 - 2 = 0 and Ha: 1 - 2 < 0

b.

H0: 1 - 2 0 and Ha: 1 - 2 = 0

c.

H0: 1 - 2 = 0 and Ha: 1 - 2 > 0

d. H0: 1 - 2 = 0 and Ha: 1 - 2 0

2.

A researcher wants to assess if the average age when women first marry has increased from 2000 to 2020. Let 1 = average age of first marriage for women in 2020 and 2 = average age of first marriage for women in 2000. A random sample of 10 women married in 2020 showed an average age at marriage of 24.95 years, with a sample standard deviation of 2 years. A random sample of 20 women married in 2000 showed an average age at marriage of 23.1 years, with a sample standard deviation of 1.5 years. Assume that age of first marriage for women is normally distributed, but do not assume the population variances are equal.What is the value of the test statistic?

Select one:

a. t = 2.33

b. t = 1.80

c. t = 2.00

d. t = 2.58

3.

Spatial perception is measured on a scale from 0 to 10. Two groups of 8th grade children are tested for spatial perception. The students in group 1 were first given a short course on spatial concepts. The students in group 2 received no such instruction. R software was used to calculate descriptive statistics for the two samples.

What is the value of the pooled standard error?

Select one:

a. 0.729

b. 0.693

c. 1.537

d.

0.483