Download Psyc 200 Statistics: Activity Approach

Psyc 200 Statistics: Activity Approach
Harry Sinnamon
Test 1 Practice
1. There are three children ages 3, 4, and 5, in a room. If a 4-year-old child enters the room
the
A) mean age will stay the same but the variance will increase.
B) mean age will stay the same but the variance will decrease.
C) mean age and variance will stay the same.
D) mean age and variance will increase.
Here is a histogram of the gold medal–winning high jumps for the Olympic Games.
2.
A)
B)
C)
D)
The mean of this histogram is approximately
75 inches.
77.5 inches.
82 inches.
90 inches.
Use the following density curve to answer the question(s) below.
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3.
A)
B)
C)
D)
For this density curve, what percent of the observations lie above 1.5?
25%
50%
75%
80%
During the early part of the 1994 baseball season, many sports fans and baseball players noticed
that the number of home runs being hit seemed to be unusually large. Below are the team-byteam statistics on home runs hit through Friday, June 3, 1994 (from the Columbus Dispatch
sports section, Sunday, June 5, 1994). Below are separate stemplots for the number of home
runs by American League and National League teams.
4.
A)
B)
C)
D)
The median for the number of home runs for the American League teams is
lower than for the National League teams.
45
50
57.5
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For a Physics course containing 10 students, the maximum point total for the quarter was 200.
The point totals for the 10 students are given in the stemplot below.
5.
A)
B)
C)
D)
To which of the following data sets does this stemplot correspond?
All integers between 116 and 179.
1, 2, 3, 4, 6, 6, 7, 8, 8, 9.
16, 18, 21, 24, 28, 33, 37, 42, 46, 79.
116, 118, 121, 124, 128, 133, 137, 142, 146, 179.
6. A researcher notices that in a sample of adults, those who take larger amounts of
vitamin C have fewer illnesses. However, those who take larger amounts of vitamin C
also tend to exercise more. As explanations for having fewer illnesses, the variables
"amount of vitamin C taken" and "amount of exercise" are
A) skewed.
B) confounded.
C) common responses.
D) symmetric.
7. In a statistics course, a linear regression equation was computed to predict the final
exam score from the score on the first test. The equation of the least-squares regression
line was
y = 10 + 0.9x
A)
B)
C)
D)
where y represents the final exam score and x is the score on the first exam. Suppose
Joe scores a 90 on the first exam. What would be the predicted value of his score on the
final exam?
91.
89.
81.
Cannot be determined from the information given. We also need to know the
correlation.
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8. An article in the student newspaper of a large university had the headline "A's swapped
for evaluations?" The article included the following.
According to a new study, teachers may be more inclined to give higher grades to
students, hoping to gain favor with the university administrators who grant tenure. The
study examined the average grade and teaching evaluation in a large number of courses
given in 1997 in order to investigate the effects of grade inflation on evaluations. "I am
concerned with student evaluations because instruction has become a popularity contest
for some teachers," said Professor Smith, who recently completed the study. Results
showed higher grades directly corresponded to a more positive evaluation.
A)
B)
C)
D)
The statement underlined above means the study found
course grade is positively associated with teaching evaluation.
teaching evaluation is negatively associated with course grade.
there was a perfect positive correlation between course grade and teaching evaluation.
all of the above.
9. I wish to determine the correlation between the height (in inches) and weight (in
pounds) of 21-year-old males. To do this I measure the height and weight of two 21year-old men. The measured values are
Height
Weight
A)
B)
C)
D)
Male #1
70
160
Male #2
75
200
The correlation r computed from the measurements on these males is
1.0.
positive and between 0.25 and 0.75.
near 0, but could be either positive or negative.
exactly 0.
10. Volunteers for a research study were divided into three groups. Group 1 listened to
Western religious music, group 2 listened to Western rock music, and group 3 listened
to Chinese religious music. The blood pressure of each volunteer was measured before
and after listening to the music, and the change in blood pressure (blood pressure before
listening minus blood pressure after listening) was recorded. To explore the relationship
between type of music and change in blood, we could
A) see if blood pressure decreases as type of music increases by examining a scatterplot.
B) make a histogram of the change in blood pressure for all of the volunteers.
C) make side-by-side boxplots of the change in blood pressure, with a separate boxplot for
each group.
D) do all of the above.
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11. A marketing research firm wishes to determine if the adult men in Laramie, Wyoming,
would be interested in a new upscale men's clothing store. From a list of all residential
addresses in Laramie, the firm selects a simple random sample of 100 and mails a brief
questionnaire to each. The chance that all 100 homes in a particular neighborhood in
Laramie end up being the sample of residential addresses selected is
A) the same as for any other set of 100 residential addresses.
B) exactly 0. Simple random samples will spread out the addresses selected.
C) reasonably large due to the "cluster" effect.
D) 100 divided by the size of the population of Laramie.
12. New varieties of corn with altered amino acid patterns may have higher nutritive value
than standard corn, which is low in the amino acid lysine. An experiment compares two
new varieties, called opaque-2 and floury-2, with normal corn. Corn-soybean meal diets
using each type of corn are prepared at three different protein levels, 12%, 16%, and
20%, giving nine diets in all. Researchers assign 10 one-day-old male chicks to each
diet and record their weight gains after 21 days. The weight gain of the chicks is a
measure of the nutritive value of their diet. The experimental units in this experiment
are
A) variety and protein level.
B) the weight gains.
C) the 90 one-day-old male chicks.
D) opaque-2 and floury-2.
13. A study of human development showed two types of movies to groups of children.
Crackers were available in a bowl, and the investigators compared the number of
crackers eaten by children watching the different kinds of movies. One kind of movie
was shown at 8 A.M. (right after the children had breakfast) and another at 11 A.M.
(right before the children had lunch). It was found that more crackers were eaten during
the movie shown at 11 A.M. than during the movie shown at 8 A.M. The investigators
concluded that the different types of movies had an effect on appetite. The results
cannot be trusted because
A) the study was not double blind. Neither the investigators nor the children should have
been aware of which movie was being shown.
B) the investigators were biased. They knew beforehand what they hoped the study would
show.
C) the investigators should have used several bowls, with crackers randomly placed in
each.
D) the time the movie was shown is a lurking variable.
14.
A)
B)
C)
The sampling distribution of a statistic is
the probability that we obtain the statistic in repeated random samples.
the mechanism that determines whether randomization was effective.
the distribution of values taken by a statistic in all possible samples of the same size
from the same population.
D) the extent to which the sample results differ systematically from the truth.
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15. A television station is interested in predicting whether or not voters in its listening area
are in favor of federal funding for abortions. It asks its viewers to phone in and indicate
whether they support or are in favor of or opposed to this. Of the 2241 viewers who
phoned in, 1574 (70.24%) were opposed to federal funding for abortions. The number
70.24% is
A) a statistic.
B) a parameter.
C) a sample.
D) a population.
16. If the individual outcomes of a phenomenon are uncertain, but there is nonetheless a
regular distribution of outcomes in a large number of repetitions, we say the
phenomenon is
A) random.
B) predictable.
C) deterministic.
D) none of the above.
17. The probability density of a random variable X is given in the figure below.
A)
B)
C)
D)
From this density, the probability that X is between 0.5 and 1.5 is
1/3.
1/2.
3/4.
1.
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18. I select two cards from a deck of 52 cards and observe the color of each (26 cards in the
deck are red and 26 are black). Which of the following is an appropriate sample space S
for the possible outcomes?
A) S = {red, black}.
B) S = {(red, red), (red, black), (black, red), (black, black)}, where, for example, (red, red)
stands for the event "the first card is red and the second card is red".
C) S = {0, 1, 2}.
D) All of the above.
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Answer Key
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
B
C
A
D
D
B
A
A
A
C
A
C
D
C
A
A
17. B
18. B
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