in schools and colleges. In a typical experiment, the radioactivity of a sample of barium-137m is measured for one minute. It is then measured for three additional one-minute periods, separated by two minutes. So data are recorded at 1, 3, 5, and 7 minutes after the start of the first counting period. The measurement units are counts. Here are the data for one of these experiments.
Time 1 3 5 7
Count 577 318 204 117
a. Using the least-squares regression equation
count = 602.8 − (74.7 ✕ time)
and the observed data, find the residuals for the counts. (Round your answers to one decimal place.)
Time 1 3 5 7
Observed Count 577 318 204 117
Predicted Count ? ? ? ?
Residual ? ? ? ?
b. Plot the residuals versus time.