The FDA wants to test the accuracy of the reported calorie content of cheeseburgers at a fast-casual restaurant chain. The restaurant chain reports that its cheeseburgers contain 650 calories. The FDA samples 100 cheeseburgers from the restaurant chain and determines that the sample average is 663 calories. Based on the sample, the FDA estimates that the standard deviation is 50 calories. What is the 80% confidence interval of the average calories in a cheeseburger from this restaurant chain (the z-score for the sample average 1.29)