Exam 7: Linear Regression

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 to predict the amount of electricity used (in kilowatt-hours)from size was completed.The residuals plot indicated that a linear model is appropriate.What are the variables and units in this regression?

A random sample of records of electricity usage of homes in the month of July gives the amount of electricity used and size (in square feet)of 135 homes.A regression was done to predict the amount of electricity used (in kilowatt-hours)from size.The residuals plot indicated that a linear model is appropriate.The model is = 1,287 + 0.3 size.The people in a house that is 2,347 square feet used 500 kilowatt-hours less than expected.How much did they use?

A golf ball is dropped from 15 different heights (in cm)and the height of the bounce is recorded (in cm. )The regression analysis gives the model = 0.4 + 0.72 drop.A golf ball dropped from 64 cm bounced 1 cm less than expected.How high did it bounce?

A sociology student does a study to determine whether people who exercise live longer.He claims that someone who exercises 7 days a week will live 15 years longer than someone who doesn't exercise at all.

A random sample of records of electricity usage of homes in the month of July gives the amount of electricity used and size (in square feet)of 135 homes.A regression was done to predict the amount of electricity used (in kilowatt-hours)from size.The residuals plot indicated that a linear model is appropriate.The model is = 1,218 + 0.3 size.What would a negative residual mean for people living in a house that is 2,495 square feet?

The relationship between the selling price (in dollars)of used Ford Escorts and their age (in years)is analyzed.A regression analysis to predict the price from the age gives the model = 14,458 - 1,472age.Predict the price of an Escort that is 8 years old.

The relationship between the number of games won by an NHL team and the average attendance at their home games is analyzed.A regression to predict the average attendance from the number of games won has an = 31.4%.The residuals plot indicated that a linear model is appropriate.What is the correlation between the average attendance and the number of games won.

The relationship between the number of games won during one season by an NHL team and the average attendance at their home games is analyzed.A regression analysis to predict the average attendance from the number of games won gives the model = -2,100 + 187 wins.Predict the average attendance of a team with 400 wins.Explain any possible problems with this prediction.

A random sample of 150 yachts sold in the Canada last year was taken.A regression analysis to predict the price (in thousands of dollars)from length (in metres)was completed.A linear model is appropriate.What are the units of the slope?

Managers rate employees according to job performance and attitude.The results for several randomly selected employees are given below.

Ten Ford Escort classified ads were selected.The age and prices of several used Ford Escorts are given in the table.

Ten students in a tutor program at Carleton University were randomly selected.Their grade point averages (GPAs)when they entered the program were less than 9.5.The following data were obtained regarding their GPAs on entering the program versus their current GPAs.

A golf ball is dropped from 15 different heights (in cm)and the height of the bounce is recorded (in cm. )The regression analysis gives the model = 0.5 + 0.71 drop.A golf ball company is trying to show that its new ball will increase your driving distance.If the new ball is dropped from several heights would the company rather see positive or negative residuals.Explain.

The relationship between the number of games won by an NHL team and the average attendance at their home games is analyzed.A regression analysis to predict the average attendance from the number of games won gives the model = -2,600 + 225 wins.One team averaged 14,865 fans at each game and won 49 times.Calculate the residual for this team and explain what it means.

Consider the four points (20,20), (30,50), (40,30),and (50,60).The least squares line is = 5 + 50x.Explain what "least squares" means using these data as a specific example.

The relationship between the number of games won by an NHL team and the average attendance at their home games is analyzed.A regression analysis to predict the average attendance from the number of games won gives the model = -3,000 + 176 wins.One team averaged 4,240 fans at each game.They won 57 times.Calculate the residual and explain what it means.

The relationship between the number of games won by an NHL team (x)and the average attendance at their home games (y)is analyzed.The mean number of games won was 70 with a standard deviation of 16.The mean attendance was 6,993 with a standard deviation of 1,400.The correlation between the games won and attendance was 0.47.