A Random Sample of Records of Electricity Usage of Homes $\hat{\text { usage }} = 1248 + 0.6$

question 12

Multiple Choice

A random sample of records of electricity usage of homes gives the amount of electricity used in July and size (in square feet) of 135 homes.A regression was done to predict the amount of electricity used (in kilowatt-hours) from size.Suppose the linear model is appropriate.The model is $\hat{\text { usage }} = 1248 + 0.6$ size.Explain what the slope of the line says about the electricity usage and home size.

• A)On average,the amount of electricity used increases by 1248 kilowatt-hours when the size of the house is increased by a square foot.
• B)On average,the size of the house increases by 1248 feet for every kilowatt-hour used.
• C)On average,the amount of electricity used is 0.6 kilowatt hours less than the size of the house.
• D)On average,the amount of electricity used increases by 0.6 kilowatt-hours when the size of the house is increased by a square foot.
• E)On average,the size of the house increases by 0.6 feet for every kilowatt-hour used.

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Definitions:

Percent Change

A mathematical calculation that describes the degree of change over time, expressed as a percentage.

Demand Curve

A graphical representation of the relationship between the price of a good and the quantity demanded for a given period.

Price Ceiling

a legally established maximum price for goods or services, aimed at keeping prices from rising to high levels.

Equilibrium

A condition in markets where supply equals demand, and there is no external pressure for change.