2.96 Least-squares regression for radioactive decay. Refer to Exercise 2.32 (page 99) for the data on radioactive decay of barium-137m. Here are the data:

Time 1 3 5 7
Count 578 317 203 118

  1. (a) Using the least-squares regression equation

    count = 602.8 − (74.7 × time)

    and the observed data, find the residuals for the counts.

  2. (b) Plot the residuals versus time.

  3. (c) Write a short paragraph assessing the fit of the least-squares regression line to these data based on your interpretation of the residual plot.