Amanufacturer produces both a deluxe and a standard model of an automatic sander designed forhomeuse. selling prices obtained from a sample of retail outlets follow.

model price ($) model price ($)
retail outlet deluxe standard retail outlet deluxe standard
1 39 27 5 40 30
2 39 28 6 39 34
3 45 35 7 35 29
4 38 30

a. the manufacturer's suggested retail prices for the two models show a $10 price differential. use a .05 level of significance and test that the mean difference between the prices of the two models is $10. calculate the value of the test statistic (to 2 decimals).
b. what is the 95% confidence interval for the difference between the mean prices of the two models (to 2 decimals)?