# Refer to Exercise 19.17. a Use whatever technique you deem necessary to check the normality…

Refer to Exercise 19.17.

a Use whatever technique you deem necessary
to check the normality requirement and for heteroscedasticity.

b Is multicollinearity a problem? Explain.

XR19-17 In an effort to explain to
customers why their electricity bills have been so high lately, and how,
specifically, they could save money by reducing the thermostat settings on both
space heaters and water heaters, an electric utility company has collected
total kilowatt consumption figures for last years winter months, as well as
thermostat settings on space and water heaters, for 100 homes. The data are
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Refer to Exercise 19.17.

a Use whatever technique you deem necessary
to check the normality requirement and for heteroscedasticity.

b Is multicollinearity a problem? Explain.

XR19-17 In an effort to explain to
customers why their electricity bills have been so high lately, and how,
specifically, they could save money by reducing the thermostat settings on both
space heaters and water heaters, an electric utility company has collected
total kilowatt consumption figures for last years winter months, as well as
thermostat settings on space and water heaters, for 100 homes. The data are
recorded in columns 1 (consumption), 2 (space heater thermostat setting) and 3
(water heater thermostat setting).

a Determine the regression equation.

b Determine the standard error of estimate,
and comment about what it tells you.

c Determine the coefficient of
determination, and comment about what it tells you.

d Test the utility of the model, and
describe what this test tells you.

e Predict the electricity consumption of a
house whose space heater thermostat is set at 21 and whose water heater
thermostat is set at 54.

f Estimate the average electricity
consumption for houses whose space heater thermostat is set at 21 and whose
water heater thermostat is set at 54.

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