Repeat Exercise 2, but now look at the relationship between length and breadth of head for first sons, and the relationship between length and breadth of head for second sons. Are the results similar for first sons and second sons? Discuss your findings.
Exercise 2
Data was collected from 25 families with at least two male children. In each family, the length and the breadth of the first son’s head and the length and breadth of the second son’s head was measured (in mm). The data are displayed in the table below.
a) Before making a scatterplot of the data, suggest what you think the relationship between the first son’s head length and the second son’s head length measures is likely to be (your first hypothesis). Repeat for the breadth of heads data.
b) Create two scatterplots of the data (ie the first versus the second son’s length measures, and the first versus the second son’s breadth measures). In each case, decide whether a linear relationship is appropriate for the data or not.
c) Are there strong outliers visible on either of the scatterplots? d) Calculate Pearson’s r for the two datasets (ie the first versus the second son’s length measures, and the first versus the second son’s breadth measures). Do these Pearson’s r statistics indicate a weak, moderate, or strong relationship between the two variables?
e) Was your hypothesis about the relationship between the two sets of measures confirmed or disconfirmed?