Let's shake on it:A random sample of12

-ounce milkshakes from12

fast-food restaurants had the following number of calories.

504

450

399

613

608

700

472

510

642

591

375

580

Send data to Excel

Assume the population standard deviation is=

92

.

Part 1 of 3

Your Answer is correct

Explain why it is necessary to check whether the population is approximately normal before constructing a confidence interval.

It is necessary to check whether the population is approximately normal because

the sample size is less than or equal to30

.

Part 2 of 3

Your Answer is incorrect

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

is not

reasonable to assume that the population is approximately normal.

Correct Answer:

It is reasonable to assume that the population is approximately normal.

Part:2 / 3

2 of 3 Parts Complete

Part 3 of 3

Your Answer is incorrect

If appropriate, construct a99.9

%

confidence interval for the mean calorie count for all12

-ounce milkshakes sold at fast-food restaurants. Round the answers to at least two decimal places.A99.9

%

confidence interval for the mean calorie count for all12

-ounce milkshakes sold at fast-food restaurants is

<

<

.