Hw 8 q 3

3. (12.5 pts} An economist studying fuel costs wants to estimate the mean price of gasoline in her state on a certain day. On that day, she takes an SRS of 12 gas stations and nds the sample mean price (in dollars per gallon) is $2.29. From historical data she knows that the population standard deviation for the price is $0.20. The prices in the sample are approximately Norma] with no distinct outliers. Based on this sample, what is the 90% confidence interval for the mean price of gasoline that day in her state