NAME:________________________
ASU ID: __________________
TU 9:15 – 10:30
STP 226 SPRING 2001
Exam 1
There are 26 questions on this test adding up to a total of 104 points.
Read all the questions carefully.
Honor Policy: By signing below you confirm that you have neither given nor
received any unauthorized assistance on this exam.
Signature: _____________________________________________________
Date: _____________________________
STP 226 Test 1
Directions:
1.
Please read the questions carefully and place your answer in the space
provided at the end of each question.
Based on a random sample of 1000 people, a researcher obtained the following
estimates of the percentage of people lacking health insurance in one U.S. city.
Age
18 – 24
25 – 39
40 – 54
55 – 65
Percentage not covered
28.2
24.9
19.1
16.5
Classify the study as either descriptive or inferential. ______________________
2.
A manager determines the average age of his employees. Decide whether this
study is descriptive or inferential.
________________________
3.
A market researcher is conducting a telephone poll. She has a list of 581
registered voters and wishes to interview a random sample of 12 of them.
Construct a list of 12 random numbers between 1 and 581 that can be used in
obtaining the required simple random sample. Use the random number table at the
end of this test and use as your starting point the digits 432 in row 13, columns
10–12. List all the random numbers that can be used to obtain the sample of 12
voters.
4.
The finalists in an essay competition are Lisa (L), Melina (M), Ben (B), Danny
(D), Eric (E), and Joan (J). Consider these finalists to be a population of interest.
The possible samples (without replacement) of size two that can be obtained from
this population of six finalists are as follows.
L,M
B,J
L,B
D,E
L,D
D,J
L,E
E,J
L,J
M,B
M,D
M,E
M,J
B,D
B,E
If a simple random sampling method is used to obtain a sample of two of the
finalists, what are the chances of selecting Lisa and Danny? ______________
5.
At one hospital in 1992, 674 women were diagnosed with breast cancer. Five
years later, 88% of the Caucasian women and 83% of the African American
women were still alive. Identify this study as an observational study or as a
designed experiment.
_____________________
STP 226 TEST 1 SPRING 2001
Copyright  Arizona State University Department of Mathematics
2
STP 226 Test 1
Use the following designed experiment to answer questions 6 – 10.
In a clinical trial, 780 participants suffering from high blood pressure were
randomly assigned to one of three groups. Over a one-month period, the first
group received a low dosage of an experimental drug, the second group received a
high dosage of the experimental drug, and the third group received a placebo. The
diastolic blood pressure of each participant was measured at the beginning and at
the end of the period and the change in blood pressure was recorded.
6.
Identify the experimental unit.
_______________________________
7.
Identify the response variable.
_______________________________
8.
Identify the factor.
_______________________________
9.
Identify the levels of the factor.
_______________________________
10.
Identify the treatments.
_______________________________
Circle the letter of the best choice in numbers 11 to 14.
11.
An education researcher randomly selects 38 schools from one school district and
interviews all the teachers at each of the 38 schools. Identify the type of sampling
used in this example.
a.
c.
12.
b.
d.
Cluster sampling
Simple random sampling
At a college there are 120 freshmen, 90 sophomores, 110 juniors, and 80 seniors.
A school administrator selects a simple random sample of 12 of the freshmen, a
simple random sample of 9 of the sophomores, a simple random sample of 11 of
the juniors, and a simple random sample of 8 of the seniors. She then interviews
all the students selected. Identify the type of sampling used in this example.
a.
c.
13.
Systematic random sampling
Stratified sampling
Simple random sampling
Cluster sampling
b.
d.
Systematic random sampling
Stratified sampling
From a group of 496 students, every 49th student starting with the 3rd student is
selected. Identify the type of sampling used here.
a.
c.
Simple random sampling
Systematic random sampling
b.
d.
Cluster sampling
Stratified sampling
STP 226 TEST 1 SPRING 2001
Copyright  Arizona State University Department of Mathematics
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STP 226 Test 1
14.
A pollster uses a computer to generate 500 numbers and then interviews the
voters corresponding to those numbers. Identify the type of sampling used in this
example.
a.
c.
15.
Stratified sampling
Systematic random sampling
b.
d.
Simple random sampling
Cluster sampling
An agricultural researcher wishes to compare the yield of four different varieties
of wheat. 64 plots of land are available for an experiment. On each plot of land
one of the varieties of wheat will be grown. At the end of the experiment the yield
for the different varieties will be compared. 32 of the plots are at one site (site A)
and the other 32 are at another site (site B). The soil at site A differs significantly
from the soil at site B. The researcher wishes to design an experiment. In this
example, why might a randomized block design, with blocking by soil type, be
preferable to a completely randomized design?
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
For numbers 16 and 17, identify the variables as either qualitative or quantitative.
16.
A monthly electric bill (in dollars).
17.
Dennis has type O blood and Eve has type A blood. _____________________
18.
Construct a frequency distribution for the given qualitative data. The blood types
of 20 people who agreed to participate in a medical study were as follows:
A
A
O
O
AB
O
B
A
O
O
A
B
O
O
O
AB
A
A
O
A
__________________________
Use the following designed to answer questions 19 – 20.
A nurse measured the blood pressure of each person who visited her clinic. Following is a
relative-frequency histogram for the systolic blood pressure readings for those people
aged between 25 and 40. The blood pressure readings were given to the nearest whole
number. Use the histogram to answer questions 18 and 19.
STP 226 TEST 1 SPRING 2001
Copyright  Arizona State University Department of Mathematics
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STP 226 Test 1
Relative
Frequency
Systolic Blood Pressure (mm Hg)
19.
Approximately what percentage of the people aged 25 – 40 had a systolic blood
pressure reading between 110 and 119 inclusive? ____________________
20.
Approximately what percentage of the people aged 25 – 40 had a systolic blood
pressure reading less than 120?
____________________
21.
Construct a pie chart representing the given data set. 300 movie critics rated a
movie. The following data give the rating distribution.
Rating
Excellent
Good
Fair
Frequency
60
150
90
Relative Frequency
0.20
0.50
0.30
STP 226 TEST 1 SPRING 2001
Copyright  Arizona State University Department of Mathematics
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STP 226 Test 1
Questions 22, 23, and 24 are based on the following.
Identify the overall shape of the distribution as (roughly) bell-shaped, triangular, uniform,
reverse J-shaped, J-shaped, right skewed, left skewed, bimodal, or multimodal.
22.
A relative frequency histogram for the sale prices of homes sold in one city during
1996 is shown below.
Relative
Frequency
Sale Price of Home ($10,000s)
________________________
23.
The ages of a group of patients being treated at one hospital for osteoporosis are
summarized in the frequency histogram below.
Frequency
Age of Patient
________________________
STP 226 TEST 1 SPRING 2001
Copyright  Arizona State University Department of Mathematics
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STP 226 Test 1
24.
A frequency histogram is given below for the weights of a sample of college
students.
Frequency
Weight (Pounds)
25.
_______________________
A machine is supposed to fill juice bottles with 16 fluid ounces of juice. The
manufacturer picks a sample of bottles which have been filled by the machine and
determines the volume of the juice in each bottle. The results are shown in the
stem-and-leaf diagram below. The leaf unit is 0.1.
15
15
15
15
15
16
16
16
16
16
1
3
45
667777
888899999
00000011111
22223333
445
66
8
What is the smallest volume of juice (in fluid ounces) measured for the bottles
sampled?
______________________________
STP 226 TEST 1 SPRING 2001
Copyright  Arizona State University Department of Mathematics
7
STP 226 Test 1
26.
A population has a J-shaped distribution. Two different samples of size 12 are
picked from the population. Two different samples of size 1000 are then picked
from the population. Do you think that the distribution of the two samples of size
12 will have roughly the same shape? Do you think that the distribution of the two
samples of size 1000 will roughly have the same shape? Explain your thinking.
_________________________________________________________________
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_________________________________________________________________
_________________________________________________________________
_________________________________________________________________
_________________________________________________________________
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STP 226 TEST 1 SPRING 2001
Copyright  Arizona State University Department of Mathematics
8