SOLUTION: what is the smallest sample size needed to estimate the mean number of days lost due to workplace injuries with error no more than 1 day and 95% confidence, given that the standard

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Question 438883: what is the smallest sample size needed to estimate the mean number of days lost due to workplace injuries with error no more than 1 day and 95% confidence, given that the standard deviation is 0.5?
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi

what is the smallest sample size needed to estimate the mean number of days

 lost due to workplace injuries with error no more than 1 day and 95%

 confidence, given that the standard deviation is 0.5?

  95% confidence ...z = 1.96

 E = z*SD/sqrt(n)

n = (z/E *SD)^2

n = (1.96/1*.5)^2 = 15.3664

 Smallest size would be 16



See Summary of vaious z values for different confidence levels

	a	a/2	crtical regions	

90%	0.1	5%	z <-1.645	z >+1.645

95%	0.05	2.50%	z <-1.96	z >+1.96

98%	0.02	1%	z <-2.33	z >+2.33

99%	0.01	0.50%	z<-2.575	z >+2.575