Household energy expenditure. Refer to the annual total household expenditure on energy from 2011 to 2020, Exercise 11.43 (p. 666). Now consider a simple linear regression model for total expenditure 
, using household expenditure on gas 
as the independent variable. Is there sufficient evidence of a negative linear relationship between total expenditure and household expenditure on liquid fuels? Test using 
. Does your conclusion change if you use 
Exercise 11.43
Household energy expenditure. Refer to the annual total household expenditure on energy from 2011 to 2020, Exercise 11.29 (p. 661). From among the variables in the file, you selected one as the dependent variable, 
, and another as the independent variable, 
, and ran a simple linear regression. Now select a different independent variable and run another simple linear regression. Which of the two independent variables is a more accurate predictor of your chosen dependent variable? Explain.
Exercise 11.29
Household energy expenditure. Refer to annual total household expenditure on energy from 2011 to 2020, Exercise 2.43 (p. 89). Recall that annual total household expenditure data (in £ million) on gas, electricity, and liquid fuels, and the total of individual household’s expenditure on energy are save in the file. Information from the first two and last two rows are listed in the table below.
a. Select one of the variables as the dependent variable, , and another as the independent variable, . Use your knowledge of the subject area and common sense to help you select the variables.
b. Fit the simple linear model, 
, to the U.K. household data. Interpret the estimates of the slope and -intercept.
Exercise 2.43
Household energy expenditure. The annual total household expenditure on energy in the United Kingdom from 2011 to 2020 was selected from the Office of National Statistics’ Consumer Trends Time Series data. The data consists of the annual total household expenditure (in £ millions) on gas, electricity, liquid fuels, and the total of individual household’s expenditure on energy which denoted as the total expenditure (in £ millions). The data are saved in the ENERGY file. The first two and last two rows are listed in the table above.
a. Calculate the average of the total expenditure on energy for the ten years (2011 to 2020) and determine whether this statistic represents a population or sample mean. Interpret this value.
b. Find the median of the total expenditure on energy for the ten years. Does this statistic represent a population or sample median? Interpret this value.
