Please respond in 150 or more words to this statement:
In order to review the calculation of Pearson=s r, I will describe a hypothetical study to determine whether people who come from large immediate families (i.e., have many siblings) tend to create large immediate families (i.e., produce many children). In this example, each “subject” is actually an entire immediate family (parents and their children). The “X” variable is the average number of siblings for the two parents (e.g., if the mother has 1 brother and 1 sister, and the father has 2 brothers and 2 sisters, X = 3), and the “Y” variable is the number of children in the selected family. The families should be selected in an independent random manner (in this case, the entire family is being selected as though a single subject). For this hypothetical example, 10 families were selected, so N = 10. The data in Table 9.1 consist of the mean number of parental siblings, X, and the number of children for each of the 10 selected families, Y, as well as the (XY) cross-products required for computing the correlation.