Exam 12: Simple Regression

A researcher's results are shown below using Femlab (labor force participation rate among females)to try to predict Cancer (death rate per 100,000 population due to cancer)in the 50 U.S.states. Which statement is valid regarding the relationship between Femlab and Cancer?

Mary used a sample of 68 large U.S.cities to estimate the relationship between Crime (annual property crimes per 100,000 persons)and Income (median annual income per capita,in dollars).Her estimated regression equation was Crime = 428 + 0.050 Income.If Income decreases by 1000,we would expect that Crime will:

Omission of a relevant predictor is a common source of model misspecification.

Pedro became interested in vehicle fuel efficiency,so he performed a simple regression using 93 cars to estimate the model CityMPG = β₀ + β₁ Weight where Weight is the weight of the vehicle in pounds.His results are shown below.Write a brief analysis of these results,using what you have learned in this chapter.Is the intercept meaningful in this regression? Make a prediction of CityMPG when Weight = 3000,and also when Weight = 4000.Do these predictions seem believable? If you could make a car 1000 pounds lighter,what change would you predict in its CityMPG?

A researcher's Excel results are shown below using Femlab (labor force participation rate among females)to try to predict Cancer (death rate per 100,000 population due to cancer)in the 50 U.S.states. Which of the following statements is not true?

A researcher's results are shown below using n = 25 observations. The 95 percent confidence interval for the slope is:

When X is farther from its mean,the prediction interval and confidence interval for Y become wider.

Which statement is not correct?

When the errors in a regression model are not independent,the regression model is said to have autocorrelation.

Find the slope of the simple regression = b₀ + b₁x.

The variable used to predict another variable is called the:

In simple linear regression,the p-value of the slope will always equal the p-value of the F statistic.

A local trucking company fitted a regression to relate the travel time (days)of its shipments as a function of the distance traveled (miles).The fitted regression is Time = -7.126 + 0.0214 Distance,based on a sample of 20 shipments.The estimated standard error of the slope is 0.0053.Find the value of t_calc to test for zero slope.

Mary noticed that old coins are smoother and more worn.She weighed 31 nickels and recorded their age,and then performed a simple regression to estimate the model Weight = β₀ + β₁ Age where weight is the weight of the coin in grams and Age is the age of the coin in years.Her results are shown below.Write a brief analysis of these results,using what you have learned in this chapter.Make a prediction of Weight when Age = 10,and also when Age = 20.What does this tell you? Is the intercept meaningful in this regression?

In a simple regression,the correlation coefficient r is the square root of R².

The correlation coefficient r measures the strength of the linear relationship between two variables.

In the model Sales = 268 + 7.37 Ads,an additional $1 spent on ads will increase sales by 7.37 percent.

Correlation analysis primarily measures the degree of the linear relationship between X and Y.

Simple regression analysis means that:

In a simple bivariate regression with 25 observations,which statement is most nearly correct?