- Own Ampul 1 The Lifetimes Of 10 Light Bulbs Were Observed In Hours As 1052 1271 836 962 1019 1051 512 1027 1219 1040 A 1 (138.3 KiB) Viewed 122 times
own ampul 1) The lifetimes of 10 light bulbs were observed in hours) as 1052 1271 836 962 1019 1051 512 1027 1219 1040 Assuming that the standard deviation for light bulbs of this type is 80 hours, find the 95% confidence interval for the mean lifetime of this type of bulb. 2) A user of a certain gauge of steel wire suspects that its breaking strength, in newtons (N), is different from that specified by the manufacturer. Consequently the user tests the breaking strength, x N, of each of a random sample of nine lengths of wire and obtains the following ordered results. 72.2 72.9 73.4 73.8 74.1 74.5 74.8 75.3 75.9 Hence calculate a 95% confidence interval for the mean breaking strength. 3) Suppose 20 donors come to a blood drive. Assume that the blood donors are not related in any way, so that we can consider them independent. The number that the donor has type-o blood is 3. Construct the confidence interval for the proportion of all population based on type-o blood type. For question 2 calculate the confidence interval for population variance with 0.05 significance level. a=005 kanal 5) To compare customer satisfaction levels of two competing cable television C, companies, 174 customers of Company 1 and 355 customers of Company 2 were c) randomly selected and were asked to rate their cable companies on a five-point scale, with 1 being least satisfied and 5 most satisfied. The survey results are summarized in the following table: Company 1 Company 2 z kellon Saylor buytre ni=174 n2=355 "x1=3.51 x2=3.24 In Sl=0.51 $2=0.52 Construction sa 99% confidence interval for ul-u2, the difference in average satisfaction levels of customers of the two companies as measured on this five-point scale.