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Question 1 (Mandatory) (0.25 points)

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The area under a normal curve is equal to 1 (100%).

1. The area under any normal curve is equal to 1. a. True

b. False

Question 1 options:

	True
	False

Question 2 (Mandatory) (0.5 points)

The diameters of red delicious apples of an orchard have a normal distribution with a mean of 3 inches and a standard deviation of 0.35 inch. One apple will be randomly chosen. What is the probability of picking an apple with diameter less than 2.5 inches?

Question 2 options:

	0.9234
	0.0446
	0.0766
	-1.43

Question 3 (Mandatory) (0.5 points)

Question 3 options:

	0.8043
	0.1957
	0.2743
	0.0643

Question 4 (Mandatory) (0.5 points)

Question 4 options:

	0.8351
	0.1068
	0.7932
	1.5

Question 5 (Mandatory) (0.5 points)

The diameters of red delicious apples of an orchard have a normal distribution with a mean of 3 inches and a standard deviation of 0.35 inch. What diameter measurement separates the smallest 33% of the apples.

Round your answer to 2 decimal places.

Question 5 options:

Question 6 (Mandatory) (0.5 points)

The age at which babies walk is normally distributed with a mean of 13 months with a standard deviation of 1.5 months. Which age separates the oldest 25% that walked?

Question 6 options:

	15.9
	14
	10.1
	13

Question 7 (Mandatory) (0.5 points)

The blood cholesterol levels of men age 55 to 64 are approximately Normal, with mean 222 milligrams per deciliter (mg/dl) and standard deviation 37 mg/dl. A high cholesterol is above 240 mg/dl.

What percent of men in this age bracket have high cholesterol? Round your answer to 1 decimal places.

Question 7 options:

Question 8 (Mandatory) (0.5 points)

The salary of a recent graduate from a northeast university with an MBA follows a normal distribution with a mean starting salary of $78,000 with a standard deviation of $15,000. You apply the normal model and discover that approximately 7.1% receive a starting salary of more than $100,000. A university administrator surveyed a random sample of 450 of their recent graduates that earned an MBA. How many of these graduates would you expect receive a starting salary of more than $100,000? Explain.

Question 8 options:

Question 9 (Mandatory) (0.25 points)

As the sample size _____, the standard deviation of the population of all sample means decreases.

Question 9 options:

	increases
	decreases

Question 10 (Mandatory) (0.5 points)

According to a Bureau of Labor Statistics, a worker in the U.S. spends on average 528 minutes a day on the job. Suppose the standard deviation of the time spent on the job is 36 minutes. What is the probability that a sample of 81 workers have a mean time more than 533 minutes?

Question 10 options:

	0.8944
	0.1056
	0.4448
	0.5552

Question 11 (Mandatory) (0.5 points)

A strength training program was administered to a population of marine recruits. The change in number of push-ups completed between the beginning and end of the program was approximately normally distributed with a mean improvement of 7.2 with a standard deviation of 2.5. What is the probability that a sample of 25 recruits will have a mean improvement of less than 8 push-ups? Round your answer to 3 decimal places.

Question 11 options:

Question 12 (Mandatory) (0.5 points)

The average amount of corn yield is normally distributed with a mean of 186.7 bushels of corn per acre, with a standard deviation of 25.6 bushels of corn. In an agricultural study, 100 randomly selected acres were harvested. What is the probability that the mean corn yield of these 100 acres is more than 190 bushels of corn? Round your answer to 3 decimal places.

Question 12 options:

M3:L3

Sampling Distribution for Proportions Questions from 14-week course

Question 13 (Mandatory) (0.25 points)

A mail-order company has a 12.5% success rate of having people purchase their products. It mails advertisements to 676 people and 10% of these people purchase products.

What is p?

Question 13 options:

	0.875
	676
	0.10
	0.125

Question 14 (Mandatory) (0.25 points)

A mail-order company has a 12.5% success rate of having people purchase their products. It mails advertisements to 676 people and 10% of these people purchase products.

What is ?

Question 14 options:

	0.875
	0.125
	0.10
	0.90

Question 15 (Mandatory) (0.5 points)

A mail-order company has a 12.5% success rate of having people purchase their products. It mails advertisements to 676 people and 10% of these people purchase products.

What is the standard deviation of the sampling distribution of proportions Round your answer to 3 decimal places.

Question 15 options:

Question 16 (Mandatory) (0.5 points)

A mail-order company has a 12.5% success rate of having people purchase their products. It mails advertisements to 676 people.

What is the probability that less than 10% of people will purchase products?

Question 16 options:

	0.225
	0.973
	0.159
	0.027

Question 17 (Mandatory) (0.5 points)

Suppose the proportion of all college students who have used marijuana in the past 6 months is p = 0.40. In a class of 125 students that are representative of all college students, would it be unusual for the proportion who have used marijuana in the past 6 months to be less than 0.34?

Question 17 options:

	Yes
	No
	Cannot be determined

Question 18 (Mandatory) (0.5 points)

Explain how you made your decision in question #17.

Question 18 options: