Professor Brehm wants to estimate how many hours per week her
students study. A simple random sample of 84 students had a mean of
12 hours of study time per week. Construct and interpret a 90%
confidence interval for the mean number of hours a student studies
per week. Assume that the population standard deviation is known to
be 2.1 hours per week. Correctly round your results to the nearest
tenth (one decimal place) in the interpretation of your interval.
Does the data suggest that students, on average, spend less than 14
hours per week studying? Explain and interpret interval.
Please show what formulas would look like in Excel, thanks!
Sample Mean (x-bar)
Given
Stand.Dev (? or s)
Sample
Size (n)
Critical
Value
Margin of
Error
Confidence Interval
(Formulas
for upper and lower limit)