SOLUTION: SAT scores are distributed with a mean of 1,500 and a standard deviation of 300. You are interested in estimating the average SAT score of first year students at your college. If y

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Question 1197459: SAT scores are distributed with a mean of 1,500 and a standard deviation of 300. You are interested in estimating the average SAT score of first year students at your college. If you would like to limit the margin of error of your 95% confidence interval to 25 points, how many students should you sample?
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!

Hi  
 95% confident  ⇒  z = 1.96
σ = 300,   ME = 25
How large of a sample size is required?
ME+=+z%2Asigma%2Fsqrt%28n%29
0r
n = %28+z%2Asigma%2FME%29%5E2
n = %28%281.96%2A300%29%2F25%29%5E2+%29%29 = 553.1904  0r sample Size =554 (always round Up)

 = CI	z = value
90%	z =1.645    
92%	z = 1.751
95%	z = 1.96   Invnorm(.975)  2-sided (.95 + .05/2 = .975 )
98%	z = 2.326  
99%	z = 2.576
Wish You the Best in your Studies.