When coastal power stations take in large quantities of cooling water, it is inevitable that a number of fish are drawn in with the water. Various methods have been designed to screen out the fish. The article

“Multiple Regression Analysis for Forecasting Critical Fish Influxes at Power Station Intakes” (Journal of Applied Ecology [1983]: 33–42) examined intake fish catch at an English power plant and several other variables thought to affect fish intake:

y fish intake (number of fish)

x1 water temperature (C)

x2 number of pumps running x3 sea state (values 0, 1, 2, or 3)

x4 speed (knots)

Part of the data given in the article were used to obtain the estimated regression equation y^ 5 92 2 2.18x1 2 19.20x2 2 9.38x3 1 2.32x4

(based on n 26). SSRegr 1486.9 and SSResid 2230.2 were also calculated.

a. Interpret the values of b1 and b4.

b. What proportion of observed variation in fish intake can be explained by the model relationship?

c. Estimate the value of s.

d. Calculate adjusted R2

. How does it compare to R2 itself?