Download STATS Final²Review²(S1)²

STATS$Final*Review*(S1)*
1) Which of these are categorical data?
A. The birth weights of anteaters
B. The lengths of anteaters
C. The different types of anteaters
D. The top speeds of anteaters
E. The prices of anteaters
2) The relationship between two variables can
be graphed using a(n)
A. histogram
B. dotplot
C. stem-and-leaf plot
D. scatter plot
E. boxplot
Use the stem-and-leaf plot for #3-5
Home Runs per team at midseason
7|17
8|5678
9|01259
10| 1 3
11| 1
12| 2
13| 0
8) In Block 1, the average for the exam was 85%
for 19 students. In Block 2, the average was
89% for 17 students. What was the overall
average for the two classes?
A. 89%
B. 87%
C. 86.9%
D. 85%
E. not given enough information to calculate
9) If the average on a test was and 82 points
with a standard deviation of 2.2, what would be
the new mean and s.d. if the teacher added 5
points to everyone’s score?
10) Which statement is true given these boxplots comparing pulse rates before and after
exercising?
8|5 represents
85 homeruns
3) What was the largest number of runs any
team hit by midseason?
4) Which best describes the data?
A. skewed; mean greater than median
B. skewed; mean less than median
C. symmetric; mean greater than median
D. symmetric; mean equal to median
E. symmetric with outliers
5) Find the median
6) Since the distribution of housing prices in a
community is usually skewed right, which
measure of center should you use for housing
prices?
A. Mean
B. Median
C. Mode
D. Outlier
E. None of the above
7) A distribution is skewed to the left and has a
mean of $19. Which is a possible value for the
median?
A. $10
B. $18
C. $20
D. $29
A. The ranges of pulse rates are the
same before and after exercise
B. More than 50% of the pulse rates
for before were less than the minimum
for after exercise
C. There was more variation in the middle
50% of pulse rates after exercising
D. The pulse rates after exercising were
always higher than before
E. There were no outliers in either case
11) Which measure of central tendency and
measure of variation should be used with a
normally distributed distribution?
A. The mean and standard deviation
B. The mean and interquartile range
C. The median and interquartile range
D. The median and standard deviation
E. The mode and interquartile range
12) What does a z-score of 2 mean for a test?
A. You missed 2 questions
B. You got twice as many right as average
C. Your grade was 2 points above average
D. Your grade was 2 s.d.s above average
E. Your IQ is 2 points higher than “normal”
Use for #13-14:
You measured the weights of members of
population W and found the weights to be
normally distributed, with a mean of 160 pounds
and a standard deviation of 25 pounds.
13) For population W, find the z-score
associated with a weight of 120 pounds.
A. z = -2.6
B. z = -1.0
C. z = -1.6
D. z = 1.0
E. z = 1.6
14) Which is a reasonable estimate for the
smallest weight in this population?
A. 60 pounds
B. 85 pounds
C. 110 pounds
D. 135 pounds
E. 160 pounds
15) What area, to the nearest whole percent,
of the normal curve is located between z = -0.6
and z = 1.4?
A. 64%
B. 91%
C. 27%
D. 50%
E. 95%
16) Applicants to a college psychology
department have normally distributed GRE
scores with a mean of 544 and a standard
deviation of 103. What percentage of applicants
scored above 450 on the GRE?
A. 82%
B. –82%
C. 26%
D. 11%
E. 1%
17) Using N(1500, 200) for the SAT test and
N(21, 3) for the ACT, if Jocelyn got an 1800 on
the SAT and a 27 on the ACT, on which test did
she actually perform better? Explain.
Use for #18-19
You have the following regression equation for
the effect of streetlights per block (x), on crimes
per month (y): yˆ = 2.4 − 0.2x
18) How many crimes a month are predicted
when there are 7 streetlights on a block?
A. 3.8
€
B. 1.7
C. 16.6
D. –11.6
E. 1.0
19) Calculate the residual for a block with 10
street-lights and 1 crime a month.
A. –0.6
B. 0.6
C. –0.4
D. 0.4
E. –1.2
20) What is the correlation coefficient, r ?
A. The strength of the relationship between
any two variables
B. The strength of the relationship between
any two numerical variables
C. The strength of the linear relationship
between any two variables
D. The strength of the linear relationship
between any two numerical variables
E. The proportion of variation of y accounted
for by the model
21) If r = 0.78 for a set of data, how does this
value change if each of the x-values are
increased by 10?
A. The new correlation coefficient will be 0.88
B. The new correlation coefficient will be 0.68
C. The correlation coefficient will not change
D. There is not enough information to tell
22) Which determines the sign of r?
A. The pattern of the residuals
B. The strength of the relationship between
variables
C. Whether the y-intercept is positive or
negative
D. Whether the value of y increases or
decreases as the value of x increases
E. Whether the sum of the squared residuals
is positive or negative
23) Find the error with this statement:
The correlation between gender and age is
0.273
24) Suppose that all sample data points are on
the same line with a positive slope. What would r
be for this sample?
A. –1.0
B. +0.99
C. +100
D. +1.0
E. same as slope of the LSRL
25) A value of r2 of 0.85 means:
A. 15% of the variation in y is explained by
the changes in x.
B. 15% of the variation in x is explained by
the changes in y.
C. 15% of the variation in x isn’t explained by
the changes in y.
D. 85% of the variation in y is explained by
the changes in x.
E. 85% of the variation in x is explained by
the changes in y.
26) True or False: An r of –1.0 proves a
strong cause and effect relationship
between x and y.
27) You’re going to test two new varieties of
fish food vs. a commonly used fish food. You set
up an experiment as follows: 60 fish are
randomly assigned to each of three different
tanks. One tank is randomly selected to receive
one of the new foods, another to receive the
other new food, and the third tank to receive the
common food. Fish growth is measured over
time. This is an example of:
A. a randomized block design
B. a double-blind matched pairs test
C. a completely randomized design with no
control group
D. a comparative block design
E. a completely randomized design with a
control group
28) As primary research for one of her books,
Shere Hite distributed 100,000 questionnaires to
women’s groups: 4,500 women responded. Hite
found that 96% of the women felt they give more
emotional support to than they get from their
husbands or boyfriends. Which of the following
best describes her sample?
A. Representative sample
B. Voluntary response sample
C. Stratified random sample
D. Systematic sample
E. Cluster sample
29) For a survey regarding the food in the
cafeteria, every 20th student to arrive at school
was interviewed. This is an example of:
A. Simple random sampling
B. Systematic sampling
C. Cluster sampling
D. Stratified sampling
E. None of these
30) To determine whether extensive exercise
lowers the resting heart rate, a study is
performed by randomly selecting 10 employees
from the 6 largest companies is the city and
recording the hours exercised per week and
resting heart rate for each. This is an example of
a(n)
A. experiment with a control group
B. experiment with blocking
C. observational study with little bias
D. observational study with volunteer bias
31) To determine if the generic brand of pet food
is better than the store brand, researchers
randomly assign the generic brand to a group of
50 dogs and randomly assign the store brand to
a group of 45 cats. Is this a good experimental
design?
A. Yes, because there was a control group
B. Yes, because it was blocked by type of pet
C. No, because more than two brands should
have been tested
D. No, because more than two types of pets
should have been used
E. No, because brand is confounded with
type of pet
32) Why would it possibly be better to conduct
an experiment rather than an observational
study?
33) If subjects in an experiment are separated
into groups of whites and non-whites prior to the
random assignment stage, we should think of
race as a (an):
A. bias
B. blocking variable
C. matched pair
D. explanatory variable
E. response variable
34) Justin Hunter has an 80% chance of making
his shot in a shoot-out. Which plan could be
used to simulate the number of shots he would
make in his next 3 attempts?
I. Let 1, 2, 3 represent making the first, 4, 5, 6
making the second and 7, 8, 9 making the third.
Generate 3 random numbers, ignoring repeats
II. Let 0, 1 represent missing a shot and 2, 3,
…9 making a shot. Generate 3 random numbers
and count how many are in 2-9, ignoring repeats
III. Let 0, 1 represent missing a shot and 2, 3,
…9 making a shot. Generate 3 random numbers
and count how many are in 2-9
A. I only
B. II only
C. III only
D. II and III
E. I, II, and III
38) A marketing survey indicates that 60% of the
population owns an automobile, 30% owns a
house and 20% owns both. What’s the
probability of owning an automobile given that a
family owns a home?
A. 0.67
B. 0.50
C. 0.33
D 0.20
39) If P(A) = 7% and P(B) = 28%, find P(A U B)
if A and B are mutually exclusive.
A. 0.02
B. 0.21
C. 0.33
D. 0.35
40) Here are the results of a survey given to 100
students about whether they have seen the
movies The Sandlot and Mean Girls.
!
!
!
!!!!!!!!!Mean Girls
The Sandlot!!
!
!
Based on the responses, what is the probability
that a student has seen Mean Girls, given that
he/she has seen at least one of the movies?
A. 0.60
B. 0.67
C. 0.89
D. 0.90
35) If you are dealt a hand of 5 cards, what is
the probability that at least one is a heart?
A. 0.222
B. 0.237
C. 0.763
D. 0.778
E. 0. 918
This two-way table gives frequencies of the
combined simple events of color and size of
marbles in a bag. Use this for #41-42
Blue
Yellow White Black
S
27
34
16
10
87
M
7
19
53
13
92
L
3
0
11
42
56
37
53
80
65
235
36) A standard 6-sided die is rolled. What is the
probability that the number rolled is even or less
than 4?
A. 1
B. 0.83
C. 0.67
D. 0.5
41) What’s the probability that a randomly
selected marble will be blue or white?
A. 0.34
B. 0.16
C. 0.50
D. 0.18
E. None of the above
37) Two events, A and B, are independent if
A. P(A) = P(A|B)
B. P(A U B) = P(A) + P(B)
C. P(A) = P(B)
D. P(A U B) = 1
42) Find the probability of a randomly drawn
marble being yellow, given that the marble is
small.
A. 0.39
B. 0.64
C. 0.14
D. 0.37
E. 0.23