Exam 14: Inference for Regression

Biologists studying the relationship between the number of Round Goby (an invasive prey fish)and the number of salmon eggs in streams believe that the deterministic component of the relationship is a straight line. A scatterplot shows that even though the general trend is linear, the points do not fall exactly on a straight line. Which of the following factors might account for the random component of this regression model?

Which of the following statements is true about prediction intervals?

Use the following information to answer the question. Below is the scatterplot showing the association between miles driven in a semi truck (x), and the amount of tread wear on the tires (y). The residual plot of the data is also shown along with a QQ plot of the residuals. -Based on the plots provided, choose the statement that best describes whether the condition for linearity does or does not hold for the linear regression model.

Researchers studying the relationship between the number of fat grams and the net weight in ounces of a fun size package of peanut M & M's believe that the deterministic component of the relationship is a straight line. A scatterplot shows that even though the general trend is linear, the points do not fall exactly on a straight line. Describe two factors that might account for the random component of this regression model.

Use the following information to answer the question. An engineer is interested in learning whether there is an association between temperature (°F)and the strength of an automotive plastic cup holder which is measured by finding the pounds per square inch (psi)it takes to break the cup holder. The computer output below shows the results from a regression model in which the breaking point in psi was predicted by the temperature. Assume that the conditions of the linear regression model are satisfied. -State the null and alternative hypothesis to test whether there is an association between temperature and break strength two different ways.

Use the following information to answer the question. The pulse rate of a random sample of 30 second graders was recorded before and after a fifteen minute recess. The output of a regression analysis for predicting pulse rate after recess from pulse rate before recess is shown. Assume that the conditions of the linear regression model are satisfied. -If the intercept was 0 and the slope was 1, explain how the linear model would be interpreted in context.

Use the following information to answer the question. An engineer is interested in learning whether there is an association between temperature (°F)and the strength of an automotive plastic cup holder which is measured by finding the pounds per square inch (psi)it takes to break the cup holder. The computer output below shows the results from a regression model in which the breaking point in psi was predicted by the temperature. Assume that the conditions of the linear regression model are satisfied. -What is the observed value of the test statistic and the p- value? Round to the nearest thousandth.

Which of the following is not true about the coefficient of determination, r2?

Use the following information to answer the question. A random sample of 30 couples who were also new home owners were asked to report the cost of their first house and their combined age when they married. The output of a regression analysis for predicting home cost from combined age is shown. Assume that the conditions of the linear regression model are satisfied. -If the slope were 1, what would that say about the association?

Use the following information to answer the question. An engineer is interested in learning whether there is an association between temperature (°F)and the strength of an automotive plastic cup holder which is measured by finding the pounds per square inch (psi)it takes to break the cup holder. The computer output below shows the results from a regression model in which the breaking point in psi was predicted by the temperature. Assume that the conditions of the linear regression model are satisfied. -State the decision regarding the null hypothesis and the correct conclusion. State your conclusion using a significance level of 5%.

Use the following information to answer the question. A high school boys cross country coach performs a regression to predict the finish times of runners in the 10k event from the number of minutes of training in the previous week. The output is shown below. Assume that the conditions of the linear regression model hold. -The coach wants to predict the finish time of his top runner who trained for 180 minutes the previous week. Should the coach use a confidence interval or a prediction interval?

Use the following information to answer the question. Below is the scatterplot showing the association between raw material (in tons)put into an injection molding machine each day (x), and the amount of scrap plastic (in tons)that is collected from the machine every 4 weeks (y). The residual plot of the data is also shown along with a QQ plot of the residuals. -Choose the statement that best describes whether the condition for linearity does or does not hold for the linear regression model.

Suppose that you were presented with data showing the association between days absent from class and final class average. Use the following residual plots, based on the data, to answer the question. -Which of the residual plots above would suggests that the condition for constant standard deviation might not be satisfied? Explain.

Use the following information to answer the question. Below is the scatterplot showing the association between raw material (in tons)put into an injection molding machine each day (x), and the amount of scrap plastic (in tons)that is collected from the machine every 4 weeks (y). The residual plot of the data is also shown along with a QQ plot of the residuals. -Choose the statement that is true about the estimators for slope and intercept of a regression line when the conditions of the linear model hold.

Use the following information to answer the question. An engineer is interested in learning whether there is an association between temperature (°F)and the strength of an automotive plastic cup holder which is measured by finding the pounds per square inch (psi)it takes to break the cup holder. The computer output below shows the results from a regression model in which the breaking point in psi was predicted by the temperature. Assume that the conditions of the linear regression model are satisfied. -State the two conditions that must be satisfied, without exception, to make inferences using a linear model.

Use the following information to answer the question. A random sample of 30 married couples were asked to report the height of their spouse and the height of their biological parent of the same gender as their spouse. The output of a regression analysis for predicting spouse height from parent height is shown. Assume that the conditions of the linear regression model are satisfied. -What is the slope of the regression line? Choose the statement that is the correct interpretation of the slope in context.

Suppose that you were presented with data showing the association between days absent from class and final class average. Which of the following residual plots below suggests that the association between number of days absent from class and final class average is linear?

Use the following information to answer the question. Below is the scatterplot showing the association between the number of workers on an assembly team (x), and the number of parts assembled in an 8- hour shift (y). The residual plot of the data is also shown along with a QQ plot of the residuals. -Use the plot(s)above to explain whether the condition for normality of errors is satisfied.

Use the following information to answer the question. A humanities professor is interesting in learning whether there is a positive association between average online homework scores and the final class average in an online humanities course. The computer output below shows the results from a regression model in which the final class average was predicted by the average online homework score. Assume that the conditions of the linear regression model are satisfied. -Choose the correct decision regarding the null hypothesis and the correct conclusion. State your conclusion using a significance level of 5%.

Choose the condition of the linear regression model that cannot by verified by examining the residuals. Choose (d)if all the conditions given can be verified by examining the residuals.