Question 1

According to the central limit theorem,the standard error for a sample mean becomes smaller as the sample size increases.

Accepted Answer

A) True 
 B)False  True

Question 2

A sample is selected from a population with a mean of µ = 40.If the sample mean is M = 45,which of the following combinations would make the sample mean an extreme,unrepresentative value for the population?

Accepted Answer

A)  A small sample and a small population standard deviation
B)  A small sample and a large population standard deviation
C)  A large sample and a small population standard deviation
D)  A large sample and a large population standard deviation C

Question 3

A sample of n = 4 scores is selected from a population with μ = 40 with σ = 8,and the sample mean is M = 43.What is the standard error for the sample mean?

Accepted Answer

A)  8
B)  4
C)  3
D)  2 B

Question 4

A random sample of n = 60 scores is selected from a population.Which of the following distributions will definitely be normal?

Accepted Answer

A)  The scores in the sample will definitely form a normal distribution.
B)  The scores in the population definitely will form a normal distribution.
C)  The distribution of sample means will definitely form a normal distribution.
D)  None of the distributions (the sample, population, or distribution of sample means)  will definitely be normal.

Question 5

What happens to the standard error of M as sample size increases?

Accepted Answer

A)  It increases.
B)  It decreases.
C)  It stays constant.
D)  The standard error does not change in a predictable manner when sample size increases.

Question 6

A sample of n = 4 scores has a standard error of 10 points.For the same population,what is the standard error for a sample of n = 16 scores?

Accepted Answer

A)  1
B)  2.5
C)  5
D)  10

Question 7

Two samples probably will have different means even if they are both the same size and they are both selected from the same population.

Accepted Answer

A) True 
 B)False

Question 8

On average,a sample of n = 16 scores from a population with σ = 10 will provide a better estimate of the population mean than you would get with a sample of n = 16 scores from a population with σ = 5.

Accepted Answer

A) True 
 B)False

Question 9

Samples of n = 4 scores are selected from a population.If the distribution of sample means has a standard error σ = 5 points,then the population from which the samples were obtained has a standard deviation of σ = 20.

Accepted Answer

A) True 
 B)False

Question 10

A sample of n = 16 scores is selected from a population with μ = 70 and σ = 8.It is very unlikely that the sample mean will be greater than 78.

Accepted Answer

A) True 
 B)False

Question 11

For a particular population,a sample of n = 4 scores has an expected value of 10.For the same population,a sample of n = 25 scores would have an expected value of _____.

Accepted Answer

A)  4
B)  8
C)  10
D)  20

Question 12

A sample of n = 100 scores is selected from a population with μ = 80 with σ = 20.On average,how much error is expected between the sample mean and the population mean?

Accepted Answer

A)  0.2 points
B)  0.8 points
C)  2 points
D)  4 points

Question 13

If random samples,each with n = 4 scores,are selected from a normal population with µ = 80 and σ = 36,what is the standard error for the distribution of sample means?

Accepted Answer

A)  4
B)  9
C)  18
D)  36

Question 14

A sample of n = 9 scores is selected from a population with μ = 50 and σ = 12.The probability of obtaining a sample mean greater than 46 is p = 0.8413.

Accepted Answer

A) True 
 B)False

Question 15

A sample of n = 16 scores is selected from a population with μ = 80 with σ = 20.On average,how much error would be expected between the sample mean and the population mean?

Accepted Answer

A)  20 points
B)  5 points
C)  4 points
D)  1.25 points

Question 16

If samples are selected from a normal population,the distribution of sample means will also be normal.

Accepted Answer

A) True 
 B)False

Question 17

A sample is selected from a population with μ = 50 and σ = 12.If the sample mean of M = 56 produces a z-score of z = +1.00,then how many scores are in the sample?

Accepted Answer

A)  2
B)  4
C)  9
D)  16

Question 18

A sample of n = 9 scores is selected from a population with µ = 40 and σ = 18.If the sample mean corresponds to z = -1.00,then the sample mean is M = 31.

Accepted Answer

A) True 
 B)False

Question 19

For a normal population with µ = 40 and σ = 10 which of the following samples is least likely to be obtained?

Accepted Answer

A)  M ≤38 for a sample of n = 4
B)  M ≤36 for a sample of n = 4
C)  M ≤38 for a sample of n = 100
D)  M ≤36 for a sample of n = 100

Question 20

A sample is selected from a population with a mean of µ = 40.If the sample mean is M = 45,which of the following combinations would make the sample mean a good,representative value for the population?

Accepted Answer

A)  A small sample and a small population standard deviation
B)  A small sample and a large population standard deviation
C)  A large sample and a small population standard deviation
D)  A large sample and a large population standard deviation

Exam 7: Probability and Samples: The Distribution of Sample Means.

According to the central limit theorem,the standard error for a sample mean becomes smaller as the sample size increases.

A sample is selected from a population with a mean of µ = 40.If the sample mean is M = 45,which of the following combinations would make the sample mean an extreme,unrepresentative value for the population?

A sample of n = 4 scores is selected from a population with μ = 40 with σ = 8,and the sample mean is M = 43.What is the standard error for the sample mean?

A random sample of n = 60 scores is selected from a population.Which of the following distributions will definitely be normal?

What happens to the standard error of M as sample size increases?

A sample of n = 4 scores has a standard error of 10 points.For the same population,what is the standard error for a sample of n = 16 scores?

Two samples probably will have different means even if they are both the same size and they are both selected from the same population.

On average,a sample of n = 16 scores from a population with σ = 10 will provide a better estimate of the population mean than you would get with a sample of n = 16 scores from a population with σ = 5.

Samples of n = 4 scores are selected from a population.If the distribution of sample means has a standard error σ = 5 points,then the population from which the samples were obtained has a standard deviation of σ = 20.

A sample of n = 16 scores is selected from a population with μ = 70 and σ = 8.It is very unlikely that the sample mean will be greater than 78.

For a particular population,a sample of n = 4 scores has an expected value of 10.For the same population,a sample of n = 25 scores would have an expected value of _____.

A sample of n = 100 scores is selected from a population with μ = 80 with σ = 20.On average,how much error is expected between the sample mean and the population mean?

If random samples,each with n = 4 scores,are selected from a normal population with µ = 80 and σ = 36,what is the standard error for the distribution of sample means?

A sample of n = 9 scores is selected from a population with μ = 50 and σ = 12.The probability of obtaining a sample mean greater than 46 is p = 0.8413.

A sample of n = 16 scores is selected from a population with μ = 80 with σ = 20.On average,how much error would be expected between the sample mean and the population mean?

If samples are selected from a normal population,the distribution of sample means will also be normal.

A sample is selected from a population with μ = 50 and σ = 12.If the sample mean of M = 56 produces a z-score of z = +1.00,then how many scores are in the sample?

A sample of n = 9 scores is selected from a population with µ = 40 and σ = 18.If the sample mean corresponds to z = -1.00,then the sample mean is M = 31.

For a normal population with µ = 40 and σ = 10 which of the following samples is least likely to be obtained?

A sample is selected from a population with a mean of µ = 40.If the sample mean is M = 45,which of the following combinations would make the sample mean a good,representative value for the population?