I need help with this question.

4. Working for a consumer protect agency, we want to check whether a 48-ounce Special

J brand cereal box really contain an average of 48 ounces of cereals. After measuring a

random sample of 18 Special J cereal boxes, we obtained the following data of 18

weights.

39.9, 42.5, 42.8, 43.8, 44.4, 45.0, 45.2, 45.4, 46.0

46.0, 46.3, 46.9, 46.9, 47.9, 49.0, 50.8, 51.3, 52.9

Assume that the weights of cereals in all boxes have a normal distribution.

(a) (13 points) Use the sample above to construct a 99% confidence interval for the

mean weight of cereals in all Special J cereal boxes.

Confidence interval:

Margin of Error:

Interpretation:

Which of the calculator procedures have you used?

ZInterval TInterval 1-PropZInt

(b) Use the sample above to test, at alpha=0.01 level of significance,

whether our suspicion that the mean weight of cereals in all of these cereal boxes

should be lower than 48 ounces should be supported.

h0: ha:

Alpha= ?

Find critical value, rejection region, and the standardized test statistic OR p-

value of the test.

Conclusion:

Interpretation: At 1% level of significance our suspicion that the mean weight of

cereals in all Special J cereal boxes is lower that 48 ounces should

be rejected; not be rejected; be supported; not be supported

Which of the calculator procedures you have used?

Z-Test T-Test 1-PropZTest