A. Exercises 8.48
A sample of 20 pages was taken without replacement from the 1,591-page visit directory
Ameritech Pages Plus lily-livered Pages. On each page, the mean scope devoted to display ads was measured (a display ad is a large block of multicolored illustrations, maps, and text). The data (in squ atomic number 18 millimeters) are shown below:
|0 260 356 403 536 0 268 369 428 536 268 396 |
|469 536 162 338 403 536 536 130 |
(a) Construct a 95 portion confidence interval for the true mean.
incriminate= 346.5
E=1.96*170.38/sqrt (20) = 74.67
95% C/I= 346.5-74.67< u < 346.5+74.67
(b) wherefore might normality be an issue here?
The 20 pages sample was not required representative of the set of Yellow Page.
(c) What sample size would be needed to obtain an defect of ±10 square millimeters with 99 percent confidence?
N=[2.576*170.38/10]^2=1926
(d) If this is not a reasonable requirement, suggest virtuoso that is.
Increase the error or lesson the confidence.
B. Exercise 8.62
In 1992, the FAA conducted 86,991 pre-employment do medicines tests on job applications were to be engaged in gumshoe and security jobs, and found that 1,143 were positive.
a) Construct a 95 percent confidence interval for the population proportion of positive drug tests.
P-Test=1143/86991=0.013139
Sigma=sqrt [pq/n]= sqrt[0.013*0.0.987/86991]=0.000384
95% C/I- 0.013-0.000753If you want to get a safe essay, order it on our website: Orderessay
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