Suppose pumpkin pies from HEB should weigh 22 ounces. However, sometimes the weight of the pies vary randomly from 19.5 to 25.3 ounces. HEB wants to estimate the mean weight of pumpkin pies to within 0.5 ounces of its true value with a 95% confidence interval . Round your critical value to 3 decimals and round your final answer to 2 decimal places.
Calculate the standard deviation .