Question 246043
Assuming the population has a normal distribution. A sample of 25 randomly selected students has a mean test score of 81.5 with a standard deviation of 10.2. 
A. contruct a 95% confidence interval for the population mean.(show all five steps please)
sample mean: 81.5
standard error: E = t*s/sqrt(25) = 2.064*10.2/sqrt(25) = 4.21
95% CI: 81.5-4.21 < u < 81.5+4.21 
95% CI: 77.29 < u < 85.71
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B. Interpret the confidence in the context of this problem.
We are 95% confident the population mean is between 77.29 and 85.71
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Cheers,
Stan H.