Chapter 7

Question 1

Mean and Standard Deviation:
a. Population of Scores
b. Sample of Scores
c. Population of Sample Means

Question 2

The standard deviation of the distribution of sample means is called

Select one:
a. the central limit theorem.
b. the sample mean
c. the expected value of the mean
d. the standard error of the mean

Answer 2

d. the standard error of the mean

Question 3

How does sample size affect the distribution of sample means?

Select one:
a. Larger samples make the standard error smaller
b. Larger samples make the distribution more skewed
c. The size of the sample does NOT affect the distribution of sample means
d. Larger samples make the expected value larger

Answer 3

a. Larger samples make the standard error smaller

Question 4

For a population with μ = 48 and σ = 12, the distribution of sample means based on n = 16 will have a standard error of________.

Select one:
a. 8
b. 3
c. 4
d. 16

Answer 4

b. 3

Question 5

Which of the following best quantifies dispersion in the distribution of sample means?

Select one:
a. the standard deviation of the population
b. the expected value
c. the standard error of the mean
d. the range of scores

Answer 5

c. the standard error of the mean

Question 6

The standard error tells you

Select one:
a. how normal the sample is
b. how different the control and experimental groups are
c. how different the subjects in the sample are from each other
d. how different the means of samples of the same size will be

Answer 6

d. how different the means of samples of the same size will be

Question 7

If you increase the size of your individual samples (e.g., going from samples with n= 5 subjects to samples with n = 50 subjects) the means of the sampling distribution of means get closer to µ.

Answer 7

False

Question 8

What can an experimenter do, besides increasing sample size, to make the standard error small?

Select one:
a. Decrease measurement error
b. Transform the data to z-scores
c. Decrease the sample size
d. Increase the sample mean

Answer 8

a. Decrease measurement error

Question 9

The SPSS Descriptives procedure offers the option to compute standard error (S.E.) of the mean.

Answer 9

True

Question 10

If the sample size is greater than 30

Select one:
a. the sampling distribution of the mean will be normal
b. s is an unbiased estimator of σ
c. Mi s a better estimator of µ
d. the sampling distribution must be standardized

Answer 10

a. the sampling distribution of the mean will be normal

Question 11

A sampling distribution can be created from the median of all possible samples of a certain size

Answer 11

True

Question 12

Why is it important for the standard error to be small?

Select one:
a. It provides for a more precise inference about the population mean
b. Because it makes random assignment unnecessary
c. It proves the Central Limit Theorem
d. Because SpongeBob Square Pants dislikes sampling error

Answer 12

a. It provides for a more precise inference about the population mean

Question 13

For a population with μ = 80 and σ = 20, the distribution of sample means based on n = 16 will have a mean value of________.

Select one:
a. 20
b. 5
c. 15
d. 80

Answer 13

d. 80

Question 14

The mean of a sampling distribution of means for samples of 50 subjects equals the mean of the population which the samples are drawn from.

Answer 14

True

Question 15

How can you tell if a symbol refers to a sample?

Select one:
a. It is always in lower case
b. It is always in upper case (capitals)
c. The symbols are Latin (like what you are reading right now)
d. The symbols are Greek

Answer 15

c. The symbols are Latin (like what you are reading right now)

Question 16

The process of statistical inference always requires checking if the sampling distribution is a normal distribution.

Answer 16

False

Question 17

8. In an IPT test of interpersonal perception accuracy with 9 scenes, a large population who guesses the answers would decode 3 questions correctly, with a standard deviation of 1.414. Thirty-six subjects take the full channel version of the test.
   What are the independent and dependent variables?

Select one:
a. IV= Amount of non-verbal information; DV: IPT score
b. IV= Correct by guessing; DV= Correct with full channel information
c. IV= There is no IV; DV= IPT Score
d. IV= Non-verbal information; DV= Verbal information

Answer 17

a. IV= Amount of non-verbal information; DV: IPT score

Question 18

8. In the sample, the probability of scoring worse than guessing was p=

Answer 18

0.22

Question 19

8. In the sample, the probability of scoring better than guessing was p=

Answer 19

0.61

Question 20

8. If the answers to the previous two questions are your only statistical evaluation, which of the following is the best conclusion?

Select one:
a. Full channel information improves accuracy relative to guessing more often than it degrades accuracy
b. Full channel information causes interpersonal perception
c. The sample should have been larger
d. Full channel information causes accuracy to improve relative to guessing

Answer 20

a. Full channel information improves accuracy relative to guessing more often than it degrades accuracy

Question 21

8.1. Which of the following normal curves best represents the population accuracy with full channel information?

Answer 21

b

Question 22

8.2. Which formula would you use to assess sampling error for samples drawn from a population who guesses?

Answer 22

b

Question 23

8. The standard error of the mean for a large population who guesses is

Answer 23

0.24

Question 24

8.3. Which picture best represents a test of whether the mean with full channel information is better than the mean with guessing?

Answer 24

a

Question 25

8. The probability that additional tests with the same sample size would have means higher than the full channel mean is?

Select one:
a. p = 0.281
b. p > 0.9999
c. p = 0.719
d. p < 0.0001

Answer 25

d. p < 0.0001

Question 26

8. Now what is the best conclusion?

Select one:
a. Non-verbal information causes accuracy to improve relative to verbal information only
b. The observed improvement in accuracy with full channel information is a small fraction of the difference due to chance
c. The observed improvement in accuracy with full channel information relative to guessing was too big to be accounted for by sampling error
d. The sample was too small to make any valid conclusion

Answer 26

c. The observed improvement in accuracy with full channel information relative to guessing was too big to be accounted for by sampling error