In a study by Yoshida (1961), the oxygen consumption of wireworm larva groups was measured at five temperatures. The rate of oxygen consumption per larva group (in milliliters per hour)€”the dependent variable€”was transformed to 0.5 less than the common logarithm. Another independent variable (other than temperature) of importance was larva group weight, which was also transformed to common logarithms. The data are given in the following table.

a. The fitted multiple regression model containing both X1 and X2 is given by
Ŷ = -0.6838 + 0.5921X1 + 0.0394X2
On the basis of this fitted model, how much of a change in oxygen consumption would be predicted for a larva group with fixed weight X1 if the temperature were increased from X2 = 20 to X2 = 25?
b. For a temperature of 20°C, compute and compare the predicted values of Ŷ for weights of 0.250 and 0.500.
c. What is R2 for each of the three models?

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Larva Group Larva Group Oxygen Consumption (Y) Weight (X) Temperature log ml/hr 0.5) ( g Consumption () Weight (X) Temperature (log ml/hr 0.5) (og cg) (an cc 0.053 0.215 0.250 0.267 0.389 0.490 0.491 0.004 0.551 0.241 0.316 0.290 0.061 0.561 0.588 0.561 0.580 0.230 0.240 20.0 30.0 0.188 0.176 0.718 30.0 0.314 0.800 0.357 0.403 0.342 0.335 0.505 0.537 0.046 25.0 25.0 25.0 0.932 0.204 0.914 0.914 0.973 1.000 0.998 0.292 0.380 0.265 0346 0.462 0.468 0.545 0.596 0.491