A sociologist is studying the relationship between parentsâ ages and their parenting practices. The sociologist collects a random sample of 20 married couples, each of whom has an eight-year-old boy.
The sociologist decides to refer to the momsâ ages as X and the dadsâ ages as Y. The sum of the momsâ ages in the sociologistâs sample is 764 years (or, written in symbols, âX = 764). The sum of the dadsâ ages in her sample is 802 years (or, written in symbols, âY = 802).
Since the sociologist is interested in how the difference in the parentsâ ages affects their parenting practices, she needs the sum of the differences in their ages, or â(Y â X). The sum of the differences in the parentsâ ages in the sociologistâs sample is years.
The sociologist decides to look at variables associated with the eight-year-old boysâ births. To do so, she wants to consider the parentsâ ages eight years ago at the time of the boysâ births. The sum of the dadsâ ages eight years ago, or â(Y â 8), is years.
The sociologist decides to convert the current ages to months. The sum of the momsâ ages in months, or â12X, is months.