Confidence intervals and sample size
A confidence interval for the price of gasoline from a random sample of 30 gas stations in a region gives the following statistics:
y = $4.49 s = $0.29
a) Find a 95% confidence interval for the mean price of regular gasoline in that region.
b) Find the 90% confidence interval for the mean.
c) If we had the same statistics from a sample of 60 sta- tions, what would the 95% confidence interval be now?