Question 1

The variance of the sampling distribution of  is ____________________ the variance of the population we're sampling from for all sample sizes.

Accepted Answer

The answer of The variance of the sampling distribution of...

Question 2

Heights of Fences
Heights of fences are normally distributed with a mean of 52 inches and a standard deviation of 4 inches.
-{Heights of Fence Narrative} Find the probability that two randomly selected fences are both under 54 inches.

Accepted Answer

The answer of Heights of Fences
Heights of fences are normally...

Question 3

If two samples are selected independently from two non-normal populations, then the sampling distribution of  is only approximately normal provided that either n1 or n2 is 30 or more.

Accepted Answer

A) True 
 B)False

Question 4

Heights of Fences
Heights of fences are normally distributed with a mean of 52 inches and a standard deviation of 4 inches.
-{Heights of Fences Narrative} Find the probability that one randomly selected fence is under 54 inches.

Accepted Answer

The answer of Heights of Fences
Heights of fences are normally...

Question 5

The probability of success on any trial of a binomial experiment is 20%.Find the probability that the proportion of success in a sample of 400 is:
a.
less than 18%.
b.
more than 18%.
c.
between 18% and 22%.

Accepted Answer

The answer of The probability of success on any trial...

Question 6

If a simple random sample of 300 observations is taken from a population whose proportion p = 0.6, then the expected value of the sample proportion  is 0.60.

Accepted Answer

A) True 
 B)False

Question 7

Which of the following is true regarding the sampling distribution of the mean for a large sample size? Assume the population distribution is not normal.

Accepted Answer

A)  It has the same shape, mean and standard deviation as the population. 
B)  It has the same mean as the population, but a different shape and standard deviation. 
C)  It the same mean and standard deviation as the population, but a different shape. 
D)  It has the same shape and mean as the population, but a different standard deviation.

Question 8

If the population distribution is unknown, in most cases the sampling distribution of the mean can be approximated by the normal distribution if the samples contain at least 30 observations.

Accepted Answer

A) True 
 B)False

Question 9

A sampling distribution is defined as the probability distribution of means from all possible sample sizes that are taken from a given population.

Accepted Answer

A) True 
 B)False

Question 10

DVD Rental Store
A DVD rental store wants to know what proportion of its customers are under age 21.A simple random sample of 500 customers was taken, and 375 of them were under age 21.Presume that the true population proportion of customers under age 21 is 0.68.
-{DVD Rental Store Narrative} Find the mean and standard deviation of  .

Accepted Answer

The answer of DVD Rental Store
A DVD rental store wants...

Question 11

Number of Fish Tanks
The following data give the number of fish tanks owned for a population of 4 families.
 
-{Number of Fish Tanks Narrative} Find the sampling distribution of  , and use it to calculate the mean and the standard deviation of  .

Accepted Answer

The answer of Number of Fish Tanks
The following data give...

Question 12

When a great many simple random samples of size n are drawn from a population that is normally distributed, the sampling distribution of the sample mean is normal regardless of the sample size n.

Accepted Answer

A) True 
 B)False

Question 13

The mean of the difference  is equal to the mean of the difference  .

Accepted Answer

A) True 
 B)False

Exam 9: Sampling Distributions

The variance of the sampling distribution of is ____________________ the variance of the population we're sampling from for all sample sizes.

Heights of Fences Heights of fences are normally distributed with a mean of 52 inches and a standard deviation of 4 inches. -{Heights of Fence Narrative} Find the probability that two randomly selected fences are both under 54 inches.

If two samples are selected independently from two non-normal populations, then the sampling distribution of is only approximately normal provided that either n₁ or n₂ is 30 or more.

Heights of Fences Heights of fences are normally distributed with a mean of 52 inches and a standard deviation of 4 inches. -{Heights of Fences Narrative} Find the probability that one randomly selected fence is under 54 inches.

The probability of success on any trial of a binomial experiment is 20%.Find the probability that the proportion of success in a sample of 400 is: a. less than 18%. b. more than 18%. c. between 18% and 22%.

If a simple random sample of 300 observations is taken from a population whose proportion p = 0.6, then the expected value of the sample proportion is 0.60.

Which of the following is true regarding the sampling distribution of the mean for a large sample size? Assume the population distribution is not normal.

If the population distribution is unknown, in most cases the sampling distribution of the mean can be approximated by the normal distribution if the samples contain at least 30 observations.

A sampling distribution is defined as the probability distribution of means from all possible sample sizes that are taken from a given population.

Number of Fish Tanks The following data give the number of fish tanks owned for a population of 4 families. -{Number of Fish Tanks Narrative} Find the sampling distribution of , and use it to calculate the mean and the standard deviation of .

When a great many simple random samples of size n are drawn from a population that is normally distributed, the sampling distribution of the sample mean is normal regardless of the sample size n.

The mean of the difference is equal to the mean of the difference .