B7. In the regression of Y on independent variables A, B, C, and D, the computer was asked for a prediction for a new point with A = 100, B = 0.74, C = 19, and D = 1.1. The output showed

95% confidence interval = (886.22, 950.08)

95% prediction interval = (673.96, 1162.34)

This means that

A. The input data are symmetrically distributed because the two intervals have the same center.

B. You are 95% confident that the corresponding new Y value will fall in the interval (886.22, 950.08).

C. The corresponding new Y value will fall in the interval (673.96, 1162.34) with probability 95%.

D. All of the above.

B8. A data spreadsheet has dependent variable Y and independent variables E, G, H, K, M, Q, R. Two regressions are done. Regression 1 uses all seven independent variables. Regression 2 uses only E, K, M, R. Which of the following statements is always true?

A. The R2 statistic for regression 1 will be greater than or equal to the R2 statistic for regression 2.

B. If the F statistic is significant (at the 5% level) for regression 2, then it will be significant (at the 5% level) for regression 1.

C. Regression 1 will have the smaller standard error of regression.

D. The estimated slopes for variables E, K, M, R will be the same for the two regressions.

B9. When Alex was in college, he was an active participant in a number of political protests, and he was instrumental in getting his school to create several new opportunities for political clubs. Alex is now 32 years old. Which of the four choices below is most likely?

A. Alex has obtained a Master's degree in business and works as a financial planner. He is married and the father of two small children.

B. Alex is the father of two small children.

C. Alex has obtained a Master's degree in business and is the father of two small children.

D. Alex works as a financial planner and is the father of two small children.

B10. Raul collected data on consumer spending on print subscriptions (meaning newspapers and magazines) in a sample involving 80 families. His concern was the mean monthly expense, and he found = sample average = $31.05 and s = sample

x

standard deviation = $12.20. His 95% confidence interval for the population mean was ($28.34, $33.76). Which of the following four statements is correct?

A. There is a 95% probability that the population mean is between $28.34 and $33.76.

B. Raul would have obtained a shorter confidence interval if he designed his work around 99% confidence.

C. It would be reasonable to wager $95 that Raul has covered the population mean against $5 that he has not covered it.

D. If Raul had used a sample of size 90, then he would always obtain a shorter confidence interval.