Question

1. For each of the following, select the best answer and circle it. a) What is a for a 60% confidence level? 40 20 0.4 L 0.2 0.04 0.02 b) Find the critical t-values corresponding to a 60% confidence level, with n = 27. +0.856 +2.162 2.158 +1.315 0.855 +1.314 c) What are the critical t-values for a confidence interval if a = 0.10 and n = 35? +1.307 1.691 2.728 +1.690 +2.724 +1.306 d) What confidence level would use the critical t-values from part c? 95% 90% 80% 20% 10% e) What is the critical t-value that would cut off the top 0.5% of all scores when df = 9? 1.833 2.262 2.821 3.250 3.690 4.781 fWhat confidence level would use the critical t-value from parte? 95% 99.75% 99.5% 90% 99% 2. The following are prices of a random sample of 18 high-definition televisions sold on shopper.cnet.com in 2010 with screen sizes between 45" and 50": 698809882968 1005 109911791230 1299 1393 14991604 1790 1999 2110 2249 2329 | 2490 A normal probability plot shows the the distribution of these data is normal. Construct a 95% confidence interval for the mean price of all HDTVs in this size range. Show formula, substitution and result

Answer 1

confidence interval = xtzs 21479.556 +1.96 x 561•3055 ris interval is (1220.25, 1738.87) a) def = -1 = 35-1 = 34 3 b) 1-0.95 - 0.05 d = 2.0 32 244 -2.03 o 2.03

1. a) a = 1-0.6 -0.4 b) t- +0.855 c) t = 2 1.691 d) 90% e) t = 3.25 6) 99.5%. 2. Here = 18. , 7 = 1479.556. Se standard deviation = 561.3055 2= 1.96 & from normal table)

14 - {r} 15 X=C(698,809,882,968,1005, 1099,1179, 1230,1299,1393, 1499,1604,1790, 1999, 2110, 2249,2329,2490) 16 mean(x) sd(x) 18 [1] 1479.556 [1] 561.3055