Use the given degree of confidence and sample data to construct a confidence interval for the population mean . Assume that the population has a normal distribution. Round your answer to 2 decimals. 15) The following data is the price of a certain food product in 10 randomly selected grocery stores (you can use the calculator to find the mean and standard deviation of the data below). 7.50 8.20 7.00 7.30 7.20 8.10 8.00 7.80 7.40 8.50 Construct a 90% confidence interval estimate of the mean price of all grocery stores selling this food product