~ 2 hours

31/40

Questions to show:

Unanswered

QUESTION 8

1 POINT

The population standard deviation for the heights of dogs, in inches, in a city is 6.9 inches. If we want to be 90% confident that the sample mean is within 2 inches of the true population mean, what is the minimum sample size that can be taken?

z0.10	z0.05	z0.04	z0.025	z0.01	z0.005
1.282	1.645	1.751	1.960	2.326	2.576

Use the table above for the z-score, and be sure to round up to the nearest integer.

Provide your answer below:

78

Formula keypad has been closed. Press Control + Backslash to open it again.

FEEDBACK

Content attribution- Opens a dialog

QUESTION 16

1 POINT

Suppose XN(8,1.5), and x=5. Find and interpret the z-score of the standardized normal random variable.

Provide your answer below:

The z-score when x=5 is . The mean is .

This z-score tells you that x=5 is standard deviations to the left of the mean.

FEEDBACK

Content attribution- Opens a dialog

QUESTION 22

1 POINT

The lengths of text messages are normally distributed with a population standard deviation of 4 characters and an unknown population mean. If a random sample of 24 text messages is taken and results in a sample mean of 22 characters, find a 90% confidence interval for the population mean. Round your answers to two decimal places.

z0.10	z0.05	z0.04	z0.025	z0.01	z0.005
1.282	1.645	1.751	1.960	2.326	2.576

You may use a calculator or the common z-values above.

Select the correct answer below:

(20.57,23.43)

(19.90,24.10)

(20.95,23.05)

(20.66,23.34)

(20.10,23.90)

(20.40,23.60)

FEEDBACK

Content attribution- Opens a dialog

QUESTION 27

1 POINT

A hospital claims that the mean wait time for emergency room patients is more than 38 minutes. Identify the null hypothesis, H0, and the alternative hypothesis, Ha, in terms of the parameter .

Select the correct answer below:

H0: =38; Ha: 38

H0: =38; Ha: 38

H0: =38; Ha: >38

H0: =38; Ha: <38

FEEDBACK

Content attribution- Opens a dialog

QUESTION 28

1 POINT

Peter has collected data to find that the finishing times for cyclists in a race has a normal distribution. Based on the Empirical Rule, what is the probability that a randomly selected race participant had a finishing time of greater than 171 minutes if the mean is 156 minutes and the standard deviation is 15 minutes? Enter your answer as a percent rounded to 2 decimal places if necessary. Include the percent symbol % in your answer.

Provide your answer below:

16%

Formula keypad has been closed. Press Control + Backslash to open it again.

FEEDBACK

Content attribution- Opens a dialog

QUESTION 29

1 POINT

The random variable X has a uniform distribution with values between 14 and 30.

What is the mean and standard deviation of X?

(Round your answer to three decimal places.)

Select the correct answer below:

mean is 22; standard deviation is 1635.333

mean is 22; standard deviation is 86-36.532

mean is 14; standard deviation is 86-36.532

mean is 14; standard deviation is 1635.333

mean is 22; standard deviation is 83-34.619

mean is 14; standard deviation is 83-34.619