Question

What is the  confidence interval for the difference between the mean prices of the two models?

Chapter 10 Assignment Save Submit Assignment for Grading Exercise 10.27 Question 3 of 3 Check My Work eBook A manufacturer produces both a deluxe and a standard model of an automatic sander designed for home use. Selling prices obtained from a sample of retail outlets follow Excel File: data10-27.xisx Model Price ($) Model Price ($) Retail Outlet Deluxe Standard Retail Outlet Delux Standard 39 39 45 27 28 35 40 30 34 29 35 Round your answers to 2 decimal places. 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 Do not reject the null hypothesis (Ho 10) b, what is the 95% confidence interval for the difference between the mean prices of the two models? (to 2 decimals) to Hide Feedback Partially Correct Check My Work

Answer 1

Deluxe	Standard	Difference
39	27	12
39	28	11
45	35	10
38	30	8
40	30	10
39	34	5
35	29	6

Sample mean of the difference, x̅_d =   8.8571
Sample standard deviation, s_d =   2.6095
Sample size,    n =   7

95% Confidence interval for the mean difference:                                  

At α = 0.05, and df = 6, two tailed critical value, t-crit = T.INV.2T( 0.05 , 6 ) =   2.447

Lower Bound     = x̅d-t-crit*sd/√n   =   6.44

Upper Bound   = x̅d+t-crit*sd/√n   =   11.27

6.44 to 11.27