Exam 16: Inference for Regression

A sample of recently trained line workers was selected to determine if there is a relationship between the number of hours of training time received by production line workers and the time it took (in minutes) for them to trouble shoot their last process problem were captured.Using the regression output is shown below, what conclusion should be made at α = .05?

A researcher gathers data on the length of essays (number of lines) and the SAT scores received for a sample of students enrolled at his university.Based on his regression results, the 95% confidence interval for the slope of the regression equation is -0.88 to 1.34.At α = 0.05, we can say ________________________ .

The number of hours of training time received by employees and the time it took (in minutes) for them to trouble shoot their last process problem was estimated using a regression equation.The 95% prediction interval for trouble shooting time with 8 hours of training was determined to be 12.822 to 19.261.The correct interpretation is ________________________ .

Based on the scatterplot of data of the number of hours of training time received by production line workers and the time it took (in minutes) for them to trouble shoot their last process problem shown, we can say that ________________________ .

A sales manager was interested in determining if there is a relationship between college GPA and sales performance (number of units sold) among salespeople hired within the last year.From the regression results shown below, identify the residual standard deviation.

When using a plot of residuals (y-axis) vs.fitted value of the dependent variable, a plot with no pattern indicates that the:

Which of the following does NOT affect the standard error of the regression slope?

A researcher is interested in developing a model that can be used to distribute assistance to low income families for food costs.She used data from a national social survey to predict weekly amount spent on food using household income (in $1000).The resulting regression equation is How much money would be needed to feed a family for a week whose household income is $12,000?

An estimated regression equation that was fit to estimate ductility in steel using its carbon content was found to be significant at α = 0.05.The 95% prediction interval for the ductility of steel with 0.5% carbon content was determined to be 0.45 to 11.59.The correct interpretation is ________________________ .

A regression equation was fit to the data showing the number of hours of training time received by production line workers and the time it took (in minutes) for them to trouble shoot their last process problem and the following histogram of residuals obtained.Based on this histogram of the residuals, we can say that the:

Consider Scatterplots 1 and 2 with fitted regression lines shown below.Which of the following statements is true?

Cars from an online service were examined to see how fuel efficiency (highway mpg) relates to cost (in dollars).According to the regression equation, a used car that costs $13,000 is predicted to get about 30.24 miles per gallon.According to the data, the car got 35 miles per gallon.What is the value of the residual for this car?

According to the plot of residuals versus fitted values below, which of the following is true?

A sales manager claims that there is a relationship between college GPA and sales performance (number of units sold) among salespeople hired within the last year.Use the regression results are shown below and set α = .05 to test his claim.

In a significant regression model determining if there is a relationship between college GPA and sales performance (number of units sold in the previous month), the 95% confidence interval for the number of units sold when GPA = 3.00 was determined to be 20.914 to 22.657.The correct interpretation is ________________________ .

As the carbon content in steel increases, its ductility tends to decrease.A researcher at a steel company measures carbon content and ductility for a sample of 15 types of steel.According to the output provided below, the standard error of the regression slope is ________________________ .

As the carbon content in steel increases, its ductility tends to decrease.A researcher at a steel company measures carbon content and ductility for a sample of 15 types of steel.Use the following regression results to find the 95% confidence interval for the slope of the regression equation.

As the carbon content in steel increases, its ductility tends to decrease.A researcher at a steel company measures carbon content and ductility for a sample of 15 types of steel.Based on these data he obtained the following regression results, which of the following statements is NOT true?

A sample of 15 recently trained line workers was selected to determine if there is a relationship between the number of hours of training time received by production line workers and the time it took (in minutes) for them to trouble shoot their last process problem were captured.Use the regression output for the independent variable shown below to find the 95% confidence interval for the slope of the regression equation.