Exam 14: Inference for Regression

Choose the statement that is true about the estimators for the slope and intercept of a regression line. Assume the conditions of the linear model hold. If all statements are true, then choose (d).

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

Explain how a residual plot can be useful in determining whether the condition for linearity and the condition for a constant standard deviation have been satisfied.

Consider the following statement: "When the conditions of the linear model hold, the estimators for slope and intercept are unbiased." What is meant by the word unbiased in this context?

Which of the following is not true about residuals? Assume the conditions of the linear model hold. If all the statements are true choose (d).

Explain the difference between confidence intervals and prediction intervals. Be sure to include the type of situation in which each type of interval would be used. Which interval is likely to be wider and why?

State the two conditions that must be satisfied, without exception, to make inferences using a linear model.

Which of the following statements is true about prediction intervals?

Which of the following statements is true about checking for the constant standard deviation condition?

If we wanted to estimate the average price of all bottles of wine with a taste score of 18, we would use a

Choose the statement(s) that are not true about the estimators for slope and intercept of a regression line when the conditions of the linear model hold. If each statement is true choose (d).

Environmental biologists studying the relationship between the number of owls in a forested region and the number of field mice in the region 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?

Use the following information for following questions:. A salesman says he can predict the sales price of used Toyota Corollas by using the equation Sale Price = 14300 - 960 Age -Using the equation above, find the predicted value for a used Toyota Corolla that is 6 years old.

Which of the following statements is true about residuals? If all of the statements are true choose (d).

A researcher wanted to see if there was a linear relationship between the length of a person's leg and the length of a person's arm. Suppose a regression analysis was run to predict the lengths of legs from the lengths of arms. What would it mean if the intercept were 6 and the slope of the regression line 1?

Many universities use ACT test scores as one criterion for admission. Admission counselors believe that the deterministic part of a regression model predicting college GPA at the end of the first year from the ACT score is a straight line. What factors might contribute to the random component? In other words, why might a student's end of year GPA not fall exactly on this line?

Which of the following is not a condition of the linear regression model?

What statement about prediction intervals and confidence intervals is true. If none of the statements is true, select (d).

A researcher wanted to see if there was a linear relationship between the heights of sons and the heights of their fathers. Suppose a regression analysis was run to predict the heights of the sons from the heights of their fathers. What would it mean if the intercept were 2 and the slope of the regression line 1?

Use the following information for following questions:. A salesman says he can predict the sales price of used Toyota Corollas by using the equation Sale Price = 14300 - 960 Age -Using the information above, find the value of the residual for a used Toyota Corolla that is 7 years old and has an actual price of $6950.