3.

The Cadet is a popular model of sport utility vehicle, known for its relatively high resale value. The bivariate data given below were taken from a sample of fteen Cadets, each bought new two years ago, and each sold used within the past month. For each Cadet in the sample, we have listed both the mileage x (in thousands of miles) that the Cadet had on its odometer at the time it was sold used and the price y (in thousands of dollars) at which the Cadet was sold used. A The least-squares regression line for these data has equation y =40.78 0.46x. This line is shown in the scatter plot below. Q Mileage, x Used selling price, y ' (in thousands) (in thousands of dollars) 20.5 30.4 28.3 25.9 "y 00 23.0 30.5 40 =' 24.2 27.3 E :9 34.3 25.5 g % > L "U 20.6 31.0 32-, C 15.4 34.2 % '\" S 23.8 28.1 g E 25.7 26.8 D \"E 27.8 30.1 " 2- 27.0 30.6 x 29 5 27 9 _/ 15 20 25 30 35 40 . . Mileagex 24.1 30.1 (in thousands) 23.2 33.9 37.6 23.0 Send data to calculator v Based on the sample data and the regression line, complete the following. 20.6 31.0 30- 4 XX 15.4 34.2 Used selling 23.8 28.1 (in thousands of 25 25.7 26.8 27.8 30.1 20 27.0 30.6 15 29.5 20 30 35 27.9 40 Mileagex 24.1 30.1 (in thousands) 23.2 33.9 37.6 23.0 Send data to calculator v Based on the sample data and the regression line, complete the following. (a) For these data, used selling prices that are greater than the mean of the used selling prices tend to be paired with X mileages that are (Choose one) V the mean of the mileages. greater than (b) According to the regression equator, for an increase of one thousand miles in Cadet mileage, there is a corresponding decrease of how many thousand dollars in the used selling price?Send data to calculator v Based on the sample data and the regression line, complete the following. 15.4 34.2 23.8 28.1 25.7 26.8 27.8 30.1 27.0 30.6 29.5 27.9 24.1 30.1 23.2 33.9 37.6 23.0 Used selling (in thousands o 30 25 20 ' l 20 2% 30 35 Mileagex (in thousands) (a) For these data, used selling prices that are greater than the mean of the used selling prices tend to be paired with mileages that are (Choose one) V the mean of the mileages. (b) According to the regression equation, for an increase of one thousand miles in Cadet mileage, there is a corresponding decrease of how many thousand dollars in the used selling price? I] 'II (A) we \"60066) .0 .1 12 a 14 Many college graduates who are employed full-time have longer than 40-hour work weeks. Suppose that we wish to estimate the mean number of hours, it, worked per week by college graduates employed full-time. We'll choose a random sample of college graduates employed full-time and use the mean of this sample to estimate u. Assuming that the standard deviation of the number of hours worked by college graduates is 6.30 hours per week, what is the minimum sample size needed in order for us to be 95% condent that our estimate is within 1.4 hours per week of 11? Carry your intermediate computations to at least three decimal places. Write your answer as a whole number (and make sure that it is the minimum whole number that satisfies the requirements). (If necessary, consult a list of formulas.) ~ 2 = 3 = 4 v 5 6 V 8 9 10 11 12 13 A scientist studying babies born prematurely would like to obtain an estimate for the mean birth weight, J, of babies born during the 24" week of the gestation period. She plans to select a random sample of birth weights of such babies and use the mean of the sample to estimate u. Assuming that the population of birth weights of babies born during the 24 " week has a standard deviation of 2.7 pounds, what is the minimum sample size needed for the scientist to be 95% confident that her estimate is within 0.5 pounds of u? Carry your intermediate computations to at least three decimal places. Write your answer as a whole number (and make sure that it is the minimum whole number that satisfies the requirements). (If necessary, consult a list of formulas.) X 5Ill 00 00 \"@609 9 1C\") Use the ALEKS calculator to solve the following problems. (a) Consider a t distribution with 26 degrees of freedom. Compute P (t2 1.19). Round your answer to at least three decimal places. P(t21.19)=|:| (b) Consider a t distribution with 4 degrees of freedom. Find the value of c such thatP(-c