1. The following problem scenario is adapted from problem 3 in Chapter 7 (p. 132) in your textbook; several of the problems that follow are also from your textbook. Meredith is interested in studying whether the amount of time spent exercising is related to overall health for adults in their 50's. She collects data on seven participants on two measures: weekly hours of exercise and a rating of overall health (higher scores indicate better health). Do problems 1a-f below by hand (i.e., do not use SPSS).

Weekly hours of exercise: 11, 9, 8, 6, 4, 3, 1 Overall health rating: 12, 8, 10, 7, 4, 6, 2

a) By hand, create a scatterplot for these data. Place hours of exercise on the horizontal axis (X) and overall health on the vertical axis (Y). Be sure you label both axes and attempt to create the plot to scale (e.g., 1 cm = 1 hour).

b) Describe this scatterplot in the context of this problem by describing the direction, shape, and strength of the association. In other words, what is the "story" conveyed by this scatterplot?

c) Do you detect any outliers or evidence of curvilinearity?

d) Based on visual inspection alone and before proceeding to the next problems, estimate the Pearson correlation coefficient, r, from this scatterplot (i.e., make your best guess regarding the value of r).

e) Compute the covariance for these data. Show your work. You might find it useful to organize your computation using a table similar to that shown in slide 14 in our class slides on Correlation.

f) Compute the correlation coefficient, r, for these data. How does this value compare to your estimate based on visual inspection in part d?