Question

1. The weights of ice cream cartons are normally distributed with a mean weight of 11 ounces and a standard deviation of 0.4 ounce.

​(a) What is the probability that a randomly selected carton has a weight greater than 11.15 ​ounces?

​(b) A sample of 36 cartons is randomly selected. What is the probability that their mean weight is greater than

11.15 ​ounces?

2.

You are given the sample mean and the population standard deviation. Use this information to construct the​ 90% and​ 95% confidence intervals for the population mean. Interpret the results and compare the widths of the confidence intervals.

From a random sample of 72 ​dates, the mean record high daily temperature in a certain city has a mean of 82.28degreesF. Assume the population standard deviation is 14.77degrees F.

the 90% confidence interval?

the 95% confidence interval?

which interval is wider? 95 or 90

interpret the results :

A.

You can be​ 90% confident that the population mean record high temperature is outside the bounds of the​ 90% confidence​ interval, and​ 95% confident for the​ 95% interval.

B.

You can be​ 90% confident that the population mean record high temperature is between the bounds of the​ 90% confidence​ interval, and​ 95% confident for the​ 95% interval.

C.

You can be certain that the population mean record high temperature is either between the lower bounds of the​ 90% and​ 95% confidence intervals or the upper bounds of the​ 90% and​ 95% confidence intervals.

D.

You can be certain that the mean record high temperature was within the​ 90% confidence interval for approximately 65 of the 72 ​days, and was within the​ 95% confidence interval for approximately 68 of the 72 days.

Answer 1