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a sociologist is found that in a random sample of 50 retired men, the average number if jobs they had during their lifetimes was 7.2. the population standard deviation is 2.1.

find the 95% confidence interval of the mean number of jobs; 

 Apr 14, 2021
 #1
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Studying a z-score table , you will find      z =  -1.96   = .025

                                                 and           z = +1.96   = .9750             .9750 - .025 = .95 = 95%

 

 

Standard deviation 2.1    ( 1.96 standard deviations above and below the mean (7.2) will encompass 95% )

7.2    -    2.1 ( - 1.96) = 3.084 jobs

7.2    +   2.1 (+1.96)  = 11.316 jobs              so I THINK the 95% confidence interval is   3.084  to 11.316 jobs      (not positive of this answer)

 Apr 14, 2021

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