0. You measure the weights of a random sample of 400 male workers in the automot
ID: 3318311 • Letter: 0
Question
0. You measure the weights of a random sample of 400 male workers in the automotive The sample mean is x = 176.2 lbs. Suppose that the weights of male workers in the automotive industry follow a normal distribution with unknown mean and standard deviation = 11.1 lbs. A 95% confidence interval for is A) (154.44, 197.96). B) (157.94, 194.46). C)) (175.11, 177.29). ) (175.29, 177.11). 31. To assess the accuracy of a laboratory scale, a standard weight that is known to weigh 1 gram is repeatedly weighed a total of n times and the mean of the weighings is computed. Suppose the scale readings are normally distributed with unknown mean and standard deviation = 0.01 g. How large should n be so that a 95% confidence interval for has a margin oferror of± 0.00012 A) 100 B) 196 C) 10000 D) 38416 Is the mean height for all adult American males between the ages of 18 and 21 now over nopulation of all adult.American males between the ages of 18 and 21 has andard deviation teet, to answer this question one would n tive hypotheses?Explanation / Answer
Solution:
30) 95% CI for using Normal dist
Sample Mean x = 176.2, n = 400
= 11.1, = 0.05
The critical value Z/2 = Z0.025 = 1.96
Margin of Error E = Z/2 *(/n) = 1.96 * 11.1/400 = 1.0878
Limits of 95% confidence interval are given by:
Lower limit = x ± E = 176.2 ± 1.0878
= (175.1122, 177.2878)
95% confidence interval (175.1122, 177.2878)
95% CI using normal dist: 175.1122 < <177.2878
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