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The mean for a sample of n = 4 scores has a standard error σM = 5 points.This sample was selected from a population with a standard deviation of σ = 20.

A) True
B) False

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The smallest possible standard error is obtained when a small sample is taken from a population with a small standard deviation.

A) True
B) False

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A researcher obtained M = 27 for a sample of n = 36 scores selected from a population with µ = 30 and s = 18.This sample mean corresponds to a z-score of z = -1.00.

A) True
B) False

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A sample of n = 4 scores is selected from a population with µ = 30 and s = 8.The probability of obtaining a sample mean greater than 34 is equal to the probability of obtaining a z-score greater than z = 2.00 from a normal distribution.

A) True
B) False

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For a population with µ = 80 and σ = 20,the distribution of sample means based on n = 16 will have an expected value of ____ and a standard error of ____.​


A) ​5; 80
B) ​80; 5
C) ​20; 20
D) ​80; 1.25

E) B) and D)
F) A) and B)

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For a normal population with µ = 100 and σ = 20: a. What is the probability of obtaining a sample mean greater than 110 for a sample of n = 4 scores? b. What is the probability of obtaining a sample mean greater than 110 for a sample of n = 16 scores? c. For a sample of n = 25 scores, what is the probability that the sample mean will be within 5 points of the population mean? In other words, what is p(95 < M < 105)?

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​a.z = 10/10 = 1.00.p = 0.1587...

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The distribution of sample means is the collection of sample means for all the possible random samples of a particular size (n)that can be obtained from a population.

A) True
B) False

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A sample is obtained from a population with s = 20.If the sample mean has a standard error of 5 points,then the sample size is n = 4.

A) True
B) False

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The law of large numbers states that the larger the sample size (n),the more probable it is that the sample mean will be close to the population mean..

A) True
B) False

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The distribution of sample means ____.​


A) ​is always a normal distribution
B) ​will be normal only if the population distribution is normal
C) ​will be normal only if the sample size is at least n = 30
D) ​will be normal if either the population is normal or the sample size is n > 30

E) None of the above
F) A) and D)

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A random sample of n = 4 scores is selected from a population.Which of the following distributions will definitively be normal?​


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

E) All of the above
F) A) and B)

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If random samples,each with n = 36 scores,are selected from a normal population with µ = 80 and σ = 18,how much difference,on average,should there be between a sample mean and the population mean?​


A) 2 points​
B) ​3 points
C) ​6 points
D) ​18 points

E) None of the above
F) A) and B)

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A random sample of n = 4 scores is obtained from a normal population with µ = 20 and σ = 4.What is the probability that the sample mean will be greater than M = 22?​


A) ​0.50
B) ​1.00
C) ​0.1587
D) ​0.3085

E) All of the above
F) A) and D)

Correct Answer

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A sample of n = 9 scores is obtained from a population with μ = 70 and σ = 18.If the sample mean is M = 76,then what is the z-score for the sample mean?​


A) ​z = 0.33
B) ​z = 0.50
C) ​z = 1.00
D) ​z = 3.00

E) B) and D)
F) A) and B)

Correct Answer

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A mathematical proposition known as the central limit theorem provides a precise description of the distribution that would be obtained if you selected every possible sample,calculated every sample mean,and constructed the distribution of the sample mean.

A) True
B) False

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What happens to the expected value of M as sample size increases?​


A) ​It also increases.
B) ​It decreases.
C) ​It stays constant.
D) ​The expected value does not change in a predictable manner when sample size increases.

E) A) and B)
F) None of the above

Correct Answer

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A sample of n = 4 scores is selected from a population with µ = 70 and s = 10.The probability of obtaining a sample mean greater than 65 is p = 0.8413.

A) True
B) False

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A sample of n = 4 scores is selected from a population with μ = 50 and σ = 12.If the sample mean is M = 56,what is the z-score for this sample mean?​


A) ​0.50
B) ​1.00
C) ​2.00
D) ​4.00

E) All of the above
F) A) and B)

Correct Answer

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A random sample of n = 9 scores is obtained from a normal population with µ = 40 and σ = 6.What is the probability that the sample mean will be greater than M = 43?​


A) 0.3085​
B) ​0.6915
C) ​0.9332
D) ​0.0668

E) B) and C)
F) All of the above

Correct Answer

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If the standard deviation for a population increases,the standard error for sample means from the population will also increase.

A) True
B) False

Correct Answer

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