I need help figuring out this problem....

Let's shake on it: A random sample of 12-ounce milkshakes from 12 fast-food restaurants had the following number of calories. 450 399 591 504 510 613 476 700 473 375 472 642 @ Send data to Excel Assume the population standard deviation is 0= 93. Explain why it is necessary to check whether the population is approximately normal before constructing a condence interval. It is necessary to check whether the population is approximately normal because the sample size is less than or equal to 30 V - Following is a dotplot of these data. Is it reasonable to assume that the population is approximately normal? 400 450 500 550 600 650 700 It E] reasonable to assume that the population is approximately normal. If appropriate, construct a 80% condence interval for the mean calorie count for all 12-ounce milkshakes sold at fast-food restaurants. Round the answers to at least two decimal places. A 80% condence interval for the mean calorie count for all 12-ounce milkshakes sold at fast- food restaurants is m