An appropriately designed and administered survey of adults is done. Among other things, they want to estimate the difference in the average age of married women and the average age of married men in marriages between a woman and a man. Three questions on the survey are "Are you currently married to a person of the opposite sex?" "What is your current age in years?" "What is your gender?" From the data on the survey, they estimate the average difference in ages of married women and married men, among the population from which the sample is drawn of married adults in marriages to a person of the opposite sex. Which of these is the correct method of analysis?
A) Hypothesis test on a difference of independent means
B) Hypothesis test on matched pairs
C) Confidence interval for a difference of independent means
D) Confidence interval for the difference of means from matched pairs