Refer to Exercise 3.

a. Plot the residuals versus the fitted values. Does the plot indicate any serious violations of the standard assumptions?

b. Plot the residuals versus the order of the data. Does the plot indicate any serious violations of the standard assumptions?

Refer to Exercise 3.

Eruptions of the Old Faithful geyser in Yellowstone National Park typically last from 1.5 to 5 minutes. Between eruptions are dormant periods, which typically last from 50 to 100 minutes. A dormant period can also be thought of as the waiting time between eruptions. The durations in minutes for 60 consecutive dormant periods are given in the following table. It is desired to predict the length of a dormant period from the length of the dormant period immediately preceding it. To express this in symbols, denote the sequence of dormant periods T₁, . . . , T₆₀. It is desired to predict T_i+1 from T_i.