An investigator at a diet center is interested in the habits of clients entering his center's weight loss program. Given the pairs of observations below, where X = number of hours per week spent watching television and Y = number of pounds gained in the past year:
a) Construct the scatterplot, (but first read d and e below).
b) Compute the correlation coefficient.
c) What is the proportion of the variation in weight gain that is associated with variation in hours spent watching TV?
d) Add the pair (X = 2, Y = 1) to the data set and recompute the correlation coefficient. What happens to the correlation?
e) Add the new point in d) to the scatterplot you constructed in a). Without calculating it, what do you think would happen to the correlation coefficient if you now also added the point (2, 9)? (Plot it, too.)
The solution provides step-by-step method for the calculation of correlation coefficient. Formula for the calculation and interpretation of the results are also included.