Deck 14: Sample Size Determination

Question 1

If the sample size is 25 and the standard deviation is 5,what is the standard error of the
Mean?

A)5.0
B)20.0
C)1.0
D)11.17
E)125.0

Answer 1

C

Question 2

If the sample size is greater than 40,and the researcher wants to be 95 percent confident that the population mean lies somewhere in a confidence interval,the population mean will be somewhere between the sample mean ________ 1.96 ________ the ________ .

A)minus;times;standard error of the mean
B)plus or minus;times;standard error of the mean
C)times;minus;standard deviation
D)plus;times;standard error of the mean
E)minus;divided by;standard deviation

Answer 2

B

Question 3

The probability of not making a Type II error is called statistical power.

Answer 3

True

Question 4

The formula for a z-score equals the score ______ the ________ ,and then ________ the
Standard deviation of the variable.

A)plus;mean;divided by
B)minus;mean;divided by
C)minus;square root of the mean;times
D)minus;mean;times
E)plus;mean;times

Question 5

If the standard deviation is 12 and the sample size is 144,what is the standard error of the
Mean?

A)0.08
B)12.00
C)41.80
D)2.30
E)1.00

Question 6

The standard normal distribution has a mean of ________ and a standard deviation of
________.

A)one;zero
B)zero;zero
C)one;one
D)zero;one
E)zero;two

Question 7

All of the following are properties of the normal distribution EXCEPT:

A)the total area under the normal curve equals one.
B)the distribution is asymmetric about its mean.
C)the normal distribution is symmetric about its mean.
D)the area between the mean and a given number of standard deviations from the mean is the same for all normal distributions.
E)the normal distribution is "bell-shaped."

Question 8

If the mean of a set of scores equals 4,what is the z-score for a score of 2 if the standard
Deviation of the scores equals 0.5?

A)─ 1.5
B)+ 1.5
C)─ 4.0
D)+ 2.5
E)+ 4.0

Question 9

In selecting probability samples,the general relationship is that the ________ the sample
Size,the ________ the sampling error.

A)smaller;smaller
B)larger;smaller
C)there is no relationship between these two concepts
D)larger;larger
E)there is a positive relationship between these two concepts

Question 10

If z = 1.96,the standard deviation is 2.5,and the error is plus or minus $0.50,what is the
Approximate sample size needed for this study?

A)96
B)25
C)19
D)48
E)49

Question 11

What type of property of the normal distribution states that,for any population,the
Distribution of sample means approaches a normal distribution as sample size increases?

A)Pascal's Law
B)Bernouli's Law
C)Standard normal distribution
D)Central limit theorem
E)Confidence interval theorem

Question 12

If z = 1.96,the standard deviation is 4.5,and the error is plus or minus $1.75,what is the
Approximate sample size needed for this study?

A)11
B)45
C)14
D)4
E)26

Question 13

In probability samples,the cost of increasing sample size rises on a linear basis.

Question 14

The normal distribution is symmetric about the mean.

Question 15

In selecting probability samples,sampling error ________ at a rate equal to the _______ of the relative _______ in sample size.

A)increases;square root;increase
B)decreases;square root;decrease
C)decreases;square root;increase
D)decreases;same rate;increase
E)increases;square root;decrease

Question 16

If z = 1.96,the standard deviation is 3.5,and the error is plus or minus $0.25,what is the
Approximate sample size needed for this study?

A)54
B)215
C)384
D)753
E)96

Question 17

The budget for a research project frequently is a major factor in setting the sample size
for the research study.

Question 18

The standard error of the mean equals the:

A)standard deviation divided by the square root of the sample size.
B)mean times the square root of the sample size.
C)standard deviation times the square root of the sample size.
D)standard deviation minus the sample size.
E)mean divided by the square root of the sample size.

Question 19

The range of values within which the population mean is expected to fall is called the:

A)standard deviation.
B)central limit theorem.
C)confidence interval about the mean.
D)range of scores.
E)standard error of the mean.

Question 20

The size of the population under study is an important part of the formulas for
determining the sample size for a study.