The following data on x 5 score on a measure of test anxiety and y 5 exam score for a sample of n 5 9 students are consistent with summary quantities given in the paper "Effects of Humor on Test Anxiety and Per- formance" (Psychological Reports [1999]: 1203-1212):
x 23 14 14 0 17 20 20 15 21
y 43 59 48 77 50 52 46 51 51
Higher values for x indicate higher levels of anxiety.
10 75.0
12 83.6
a. Construct a scatterplot of y = percentage who said they were more likely to purchase and x = grade. Does there appear to be a linear relationship between x and y?
b. Find the equation of the least-squares line.