Question 1
A jar contains 10 red marbles and 30 blue marbles. What
is the probability of randomly selecting a red marble from the jar?
Select one:
a. 10/40
b. 10/30
c. 1/10
d. 1/40
Question 2
A normal distribution has a mean of µ = 100 with =
20. If one score is randomly selected from this distribution,
what is theprobability that the score will have a value between X =
90 and X = 110?
Select one:
a. 0.6915
b. 0.3830
c. 0.1915
d. 0.3085
Question 3
A normal distribution has a mean of µ = 100 with =
20. If one score is randomly selected from this
distribution, what is theprobability that the score will have a
value between X = 80 and X = 100?
Select one:
a. 0.1587
b. 0.3413
c. 0.8413
d. 0.6826
Question 4
A normal distribution has a mean of µ = 70 with =
12. If one score is randomly selected from this
distribution, what is theprobability that the score will be less
than X = 76?
Select one:
a. 0.1915
b. 0.3085
c. 0.6915
d. 0.3830
Question 5
A normal distribution has µ = 80 and = 10. What
is the probability of randomly selecting a score greater than 90
from this distribution?
Select one:
a. p = 0.1587
b. p = 0.6915
c. p = 0.3085
d. p = 0.8413
Question 6
A random sample of n = 4 scores is selected from a
population. Which of the following distributions definitely
will be normal?
Select one:
a. Neither the sample, the population, nor the
distribution of sample means will definitely be normal.
b. The scores in the sample will form a normal
distribution.
c. The distribution of sample means will form a normal
distribution.
d. The scores in the population will form a normal
distribution.
Question 7
A researcher conducts an experiment to determine whether
moderate doses of St. Johns Wort have any effect of memory for
college students. For this study, what is the independent
variable?
Select one:
a. The amount of St. Johns Wort given to each
participant
b. The group of college students
c. This cannot be answered without more information.
d. The memory score for each participant
Question 8
A researcher is curious about the average monthly cell phone
bill for high school students in the state of Florida. If
this average could be obtained, it would be an example of a ____.
Select one:
a. statistic
b. parameter
c. population
d. sample
Question 9
A researcher records the change in weight (gain or lost)
during the first semester of college for each individual in a group
of 25 freshmen, and calculates the average change in weight.
The average is an example of a ____.
Select one:
a. variable
b. parameter
c. constant
d. statistic
Question 10
A researcher uses an anonymous survey to investigate the
study habits of American college students. Based on the set
of 56 surveys that were completed and returned, the researcher
finds that these students spend an average of 4.1 hours each week
working on course material outside of class. For this study, the
average of 4.1 hours is an example of a ____.
Select one:
a. statistic
b. population
c. sample
d. parameter
Question 11
A sample has M = 72 and s = 4. In this sample, what is
the X value corresponding to z = -2.00?
Select one:
a. X = 60
b. X = 68
c. X = 64
d. X = 70
Question 12
A sample of n = 100 scores is selected from a population with
= 80 with = 20. On average, how much error is expected
between the sample mean and the population mean?
Select one:
a. 2 points
b. 0.8 points
c. 4 points
d. 0.2 points
Question 13
A sample of n = 25 scores has M = 20 and s2 = 9. What
is the sample standard deviation?
Select one:
a. 4.5
b. 9
c. 3
d. 81
Question 14
A sample of n = 4 scores has a mean of M = 8. If one
new score with a value of X = 3 is added to the sample, what will
be the value for the new mean?
Select one:
a. M = 8.75
b. M = 8
c. It cannot be determined with the information
provided.
d. M = 7
Question 15
A sample of n = 9 scores has a standard error of 6.
What is the standard deviation of the population from which the
sample was obtained?
Select one:
a. 6
b. 18
c. 2
d. 54
Question 16
Remove flag
Figure 2-2
What is the shape for the distribution shown in the
accompanying graph?
Select one:
a. positively skewed
b. symmetrical
c. normal
d. negatively skewed
Question 17
Figure 2.1
For the distribution in the accompanying graph, what is the
value of X?
Select one:
a. 21
b. 30
c. 15
d. cannot be determined
Question 18
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 ____.
Select one:
a. 8
b. 10
c. 4
d. 20
Question 19
For a population with a standard deviation of = 6, what is
the z-score corresponding to a score that is 12 points above the
mean?
Select one:
a. z = 12
b. z = 6
c. z = 2
d. z = 1
Question 20
For a research study, comparing attitude scores for males and
females, participant gender is an example of what kind of variable?
Select one:
a. an independent variable
b. a quasi-independent variable
c. a quasi-dependent variable
d. an dependent variable
Question 21
For the distribution in the following table, what is the 90th
percentile?
X
c%
9 100%
8
80%
7
50%
6
25%
Select one:
a. X = 8
b. X = 9.5
c. X = 8.5
d. X = 9
Question 22
For the distribution in the following table, what is the 90th
percentile?
X
c%
30-34 100%
25-29 90%
20-24 60%
15-19 20%
Select one:
a. X = 24.5
b. X = 29.5
c. X = 29
d. X = 25
Question 23
For the distribution in the following table, what is the
percentile rank for X = 7?
X
c%
9 100%
8
80%
7
50%
6
25%
Select one:
a. X = 37.5%
b. X = 65%
c. X = 50%
d. X = 80%
Question 24
For the following distribution of quiz scores, How many
individuals had a score of X = 2?
X f
5 6
4 5
3 5
2 3
1 2
Select one:
a. 5
b. 3
c. cannot be determined
d. 1
Question 25
For the following distribution, what is the highest score?
X f
20-25 2
15-19 5
10-14 4
5-9 1
Select one:
a. 20
b. 25
c. cannot be determined
d. 5
Question 26
For the following frequency distribution of exam scores, how
many students had scores lower than X = 80?
X f
90-94 3
85-89 4
80-84 5
75-79 2
70-74 1
Select one:
a. 2
b. 3
c. cannot be determined
d. 7
Question 27
For the following frequency distribution of quiz scores, how
many individuals took the quiz?
X f
5 6
4 5
3 5
2 3
1 2
Select one:
a. cannot be determined
b. n = 21
c. n = 15
d. n = 5
Question 28
If an entire population with = 60 and = 8 is transformed
into z-scores, then the distribution of z-scores will have a mean
of ____ and a standard deviation of ____.
Select one:
a. 60 and 8 (unchanged)
b. 0 and 8
c. 60 and 1
d. 0 and 1
Question 29
If sample variance is computed by dividing SS by df = n - 1,
then the average value of the sample variances from all the
possible random samples will be ____ the population variance.
Select one:
a. larger than
b. unrelated to
c. exactly equal to
d. smaller than
Question 30
If the following scores were placed in a stem and leaf
display, how many leaves would be associated with a stem of 6?
Scores: 26, 45, 62, 11, 21, 55, 66
64, 55, 46, 38, 41, 27, 29
36, 51, 32, 25, 34, 44, 59
Select one:
a. 1
b. 2
c. 3
d. 4
Question 31
In a population of scores, X = 83 corresponds to z = -0.50
and X = 93 corresponds to z = +2.00. What are the values for
the population mean and standard deviation?
Select one:
a. = 81 and = 6
b. = 85 and = 4
c. = 85 and = 2
d. = 81 and = 4
Question 32
In a population with = 8, a score of X = 44 corresponds to
a z-score of z = -0.50. What is the population mean?
Select one:
a. = 40
b. = 52
c. = 48
d. = 36
Question 33
In a sample of n = 6 scores, the smallest score is X = 3, the
largest score is X = 10, and the mean is M = 6. If the
largest score is changed from X = 10 to X = 22, then what is the
value of the new mean?
Select one:
a. The mean is still M = 6.
b. The mean is M = 7.
c. It is impossible to determine from the information
given.
d. The mean is M = 8.
Question 34
One sample has n = 4 scores and M = 10. A second sample
has n = 6 scores and M = 5. If the two samples are combined,
then what is the mean for the combined sample?
Select one:
a. 70/6 = 11.67
b. It cannot be determined with the information given.
c. 70/4 = 17.5
d. 70/10 = 7
Question 35
The average verbal SAT score for the entire class of entering
freshmen is 530. However, if you select a sample of 20
freshmen and compute their average verbal SAT score you probably
will not get exactly 530. What statistical concept is used to
explain the natural difference that exists between a sample mean
and the corresponding population mean?
Select one:
a. parametric error
b. sampling error
c. statistical error
d. inferential error
Question 36
The students in a psychology class seemed to think that the
midterm exam was very easy. If they are correct, what is the most
likely shape for the distribution of exam scores?
Select one:
a. symmetrical
b. normal
c. negatively skewed
d. positively skewed
Question 37
There is a six-point difference between two sample
means. If the two samples have the same variance, then which
of the following values for the variance would make the mean
difference easiest to see in a graph showing the two distributions.
Select one:
a. s2 = 8
b. s2 = 2
c. s2 = 16
d. s2 = 64
Question 38
What frequency distribution graph is appropriate for scores
measured on a nominal scale?
Select one:
a. only a bar graph
b. only a polygon
c. only a histogram
d. either a histogram or a polygon
Question 39
What is the first step to be performed in the following
mathematical expression? (X)2
Select one:
a. Square each score.
b. Add the squared scores.
c. Square the sum of the scores.
d. Add the scores.
Question 40
What is the mode for the population of scores shown in the
frequency distribution table?
X f
5 1
4 2
3 3
2 4
1 2
Select one:
a. 3.5
b. 4
c. 2
d. 3
Question 41
What is the value of (X)2 for the following scores?
Scores: 1, 5, 2
Select one:
a. 16
b. 10
c. 30
d. 64
Question 42
What is the value of (X + 1) for the following scores?
Scores: 2, 4, 7
Select one:
a. 10
b. 16
c. 13
d. 11
Question 43
What is the value of (X - 2 )2 for the following
scores? Scores: 2, 3, 5
Select one:
a. 8
b. 16
c. 36
d. 10
Question 44
What is the value of SS (sum of squared deviations) for the
following population?
Population: 2, 3, 0, 5
Select one:
a. 13/4 = 3.25
b. 38/4 = 9.50
c. 13
d. 38
Question 45
What is the value of SS for the following set of
scores? Scores: 1, 1, 4, 0
Select one:
a. 18
b. 9
c. 6
d. 10
Question 46
What is the variance for the following population of
scores? Scores: 5, 2, 5, 4
Select one:
a. 6
b. 2
c. 1.22
d. 1.5
Question 47
What term is used to describe the shape of a distribution in
which the scores pile up on the lefthand side of the graph and
taper off to the right?
Select one:
a. symmetrical
b. positively skewed
c. normal
d. negatively skewed
Question 48
What z-score value separates the top 70% of a normal
distribution from the bottom 30%?
Select one:
a. z = -0.52
b. z = 0.84
c. z = -0.84
d. z = 0.52
Question 49
You are instructed to subtract four points from each score
and find the sum of the resulting values. How would this set
of instructions be expressed in summation notation?
Select one:
a. 4 - X
b. X - 4
c. (X - 4)
d. (4 - X)
Question 50
You have a score of X = 65 on an exam. Which set of
parameters would give you the best grade on the exam?
Select one:
a. = 60 and = 5
b. = 60 and = 10
c. = 70 and = 5
d. = 70 and = 10
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