2) To compare two kinds of bumper guards, ten of each kind were mounted on a certain make midsize car. Then each car was run into a concrete wall at 5 miles per hour, and following are the costs of the repairs (in dollars) assumed normally distributed: Bumper guard A: 545 495 506 447 530 510 487 539 559 531 Bumper guard B: 536 514 475 513 558 546 517 473 562 529 a) Test whether the mean cost with bumper guard A is lower than $500 at .05 level. b) Test whether the mean cost with bumper guard B is higher than $500 at .05 level. c) Obtain 95% confidence interval for the difference between the mean costs with bumper guard A and B. d) Use the 0.05 level of significance to test whether the difference between the corrosponding sample means is significant.

Find the total net cost of the shipment of materials shown in this figure. ITEM QUANTITY LIST $4.00 each Floor Box 10 -Inch Conduit 250 $2.26 each 250 $4.14 each Single-Pole Key Socket Body Single-Pole Flush Switch 35 $1.27 each DISCOUNT 20% 25% 40% 40%

according to the department of cars ,trucks , and light duty trucks are driven on an average of about 12,000miles per year,and consume  on an average roughly 700 gallons of gas. A. What is the average  fuel economy in miles per gallon obtained by these vehicles? B.How meny gallons of gas would the average vehicle save each year if average fuel economy increased by 4 miles per gallon? C Assuming that 21.9 pounds of CO2 are emitted for every gallon of gas consumed, how meny fewer pounds of CO2 would the average vehicle emit annually with a 4 miles per gallon increase in fule economy?

The formula for the best fit line is y= -72359.6+216.2x, where y is sales price and x is square footage of the house. One house in this data set has 3,140 square feet of living space and sold for $485,000. Calculate the residual of this data point: a) -16859.6 b)16859.6 c)-121384.26 d)121384.26 e)none of the above