A random sample of 30 women drank an average of 15 cups of coffee per week during examination finals,

Question

with the sample standard deviation equal to 3 cups. A upper limit of an approximate confidence interval
with 95% of the population average cup drunk is ?

Answer 1

95% confidence interval = μ ± 1.96 SE

Standard Error (SE) = SD/√(n-1)

Z = (x-μ)/SE

1.96 = (x-15)/SE

Solve for x.

I hope this helps.