Data from the 2016 American Community Survey showed that 23% of opposite-

sex couples and 15.7% of same-sex couples had at least one member of the couple who was sixty-five years of age or older. Say that sample sizes are 450 for opposite-sex couples and 200 for same-sex couples. Do opposite-sex couples really skew older than same-sex couples in the population?

a. State the null and alternative hypotheses that would test this question.

b. Estimate the standard error for the difference between these proportions.

c. Calculate the sample z-score.

d. Assuming an alpha-level of .025, should the null hypothesis be rejected?

Explain how you know.

e. Offer an explanation for this finding.