A researcher wants to determine if daily walks together strengthen a marriage. One group of wives and one group of husbands are selected and take walks each day. After 2 weeks, all are asked if they felt their marriage was stronger based on the walks and the results of the two groups are compared. To be a valid matched pair test, what should the researcher consider in creating the two groups?

That the husbands and wives selected were married to each other

That the both groups were positive on marriage before the walks

That all husbands and wives in the test had been married about the same amount of time

That the wives group was positive on marriage before the walks