Download SAMPLE EXAM 1

SAMPLE EXAM 1
STAT 145
Multiple Choice (all 25 questions worth 2 points each)
In an introductory statistics class with 136 students, the professor recorded how much
money each student had in his/her possession during the first class of the semester.
The histogram below shows the data collected. Use this information to answer
questions 1 – 5.
1)
The total number of students with more than $40.00 in their possession is
closest to:
a)
b)
c)
d)
2)
The percentage of students with more than $10.00 but less than $30.00 is
closest to
a)
b)
c)
d)
3)
20%
46%
63%
88%
The third quartile for this distribution occurs in which class interval?
a)
b)
c)
d)
4)
5
10
30
128
10-20
20-30
30-40
40-50
If the outlier on the right is removed, the value of the mean will:
a) increase
b) decrease
c) stay the same
d) not enough information to answer
5)
The mean for this distribution would be
a)
b)
c)
d)
to the right of the median
to the left of the median
the same as the median
greater than $100.00
Below are side-by-side box plots comparing the pulse rates of those students in an
introductory statistics class who ran before taking their pulse rate (group 1) and
those who did not run before taking their pulse rate (group 2).
to answer questions 6 - 7.
Use these box plots
6) Which group has a greater proportion of its observations below a pulse rate of
82?
a)
b)
c)
d)
7)
Approximately 25% of the students in group 1 had a pulse rate above:
a)
b)
c)
d)
8)
.
9)
The
0
6.245
16.667
39.000
In the early part of the 20th century it was noticed that, when viewed over
time, the number of crimes increased with membership in the Church of England.
The most likely explanation for this is:
a)
b)
c)
d)
10)
58
76
88
106
Three randomly selected students had quiz scores of -4, 5, and 8.
standard deviation for this sample is:
a)
b)
c)
d)
.
.
group 1
group 2
they would be about the same
not enough information
Church leaders were encouraging their members to commit crimes.
Both crimes and Church membership increased as the population increased.
Crime rate is a lurking variable.
Church membership is a lurking variable.
Which of the following statements is true:
a)
b)
c)
c)
the mean of a sample is always greater than the std. dev. of the sample.
the std. dev. for a data set with 3 observations must always be positive.
the 3Q of a data set must always be greater than the 1Q of the data set.
the mean of a data set can be negative but the std. dev. of a data set can
never be negative
11). You have the weights in milligrams of 17 adult fleas. You find the standard
deviation of the weights to be 17.003. The correct unit for the standard deviation in
this problem is:
a)
b)
c)
d)
no units -- the standard deviation is just a number
grams squared
milligrams
milligrams squared
(Problems 12 and 13) A sample of 20 employees from the local Honda plant was obtained
and the length of time (in months) worked was recorded for each employee. A stemplot
of these data follows. In the stemplot, 5|2 represents 52 months.
5
6
7
8
9
24899
03567789
347899
8
12. The mean length of time (in months) worked for these 20 employees is
a. 66.
b. 67.
c. 67.5.
d. 68.25.
13. The first quartile of the length of time (in months) worked for these 20 employees
is
a. 5.5.
b. 59.5.
c. 75.5.
d. 67.
(Problems 14 and 15) Consumers Union measured the gas mileage per gallon of 38 1998-99 model
automobiles on a special test track.
The following pie chart provides information about the
country of manufacture of the model cars that Consumers Union used.
U.S.
France
Germany
Sweden
Japan
Italy
14. Based on this pie chart, we may conclude that
a. Japanese cars get significantly lower gas mileage than cars of other countries. This is
because their slice of the pie is at the bottom of the chart.
b. more than half of the cars in the study were from the U.S.
c. Swedish cars get gas mileages that are between those of Japanese and U.S. cars.
d. Mercedes Benz, Audi, Porsche, and BMW represent approximately a quarter of the cars
tested.
15.
Which of the following bar graphs is equivalent to the pie chart?
a.
15
10
5
France Germany Italy
Japan
Sweden
U.S.
France Germany Italy
Japan
Sweden
U.S.
b.
25
20
15
10
5
c.
d.
16. The five-number summary of a set of data
a.
b.
c.
d.
is the
is the
can be
is the
mean, standard deviation, first quartile, median, and third quartile.
mean, median, mode, variance, and standard deviation.
computed from the information in a stemplot.
minimum, the interquartile range, the mean, the median, and the maximum.
17. The average salary of all female workers at a large plant is $35,000. The average
salary of all male workers at the plant is $41,000. If there are more male workers
than female workers at the plant, then the average salary at the plant must be
a.
b.
c.
d.
exactly $38,000.
larger than $38,000.
smaller than $38,000.
above $41,000.
Use the following density curve to answer questions 18 – 20.
18. For this density curve, the third quartile is
a.
b.
c.
d.
0.5.
0.75.
1.5.
1.75.
19. For this density curve, what percent of the observations lie between 0.25 and
0.50?
a.
b.
c.
d.
0.25%
12.5%
25%
50%
20.
Scores on a University exam are normally distributed with a mean of 68 and a
standard deviation of 9. Using the 68-95-99.7 rule, what percentage of students score
above 77?
a.
b.
c.
d.
2.5%
5%
16%
32%
21. The time to complete a standardized exam is approximately normal with a mean of 70
minutes and a standard deviation of 10 minutes.
Using the 68-95-99.7 rule, if
students are given 90 minutes to complete the exam, what percentage of students will
not finish?
a.
b.
c.
d.
32%
5%
2.5%
0.0015%
22. Using the standard normal distribution tables, what is the area under the standard
normal curve corresponding to Z < 1.15?
a.
b.
c.
d.
0.1357
0.8643
0.8749
0.9332
23. The scores on a university examination are normally distributed with a mean of 62
and a standard deviation of 11. If the bottom 5% of students will fail the course,
what is the lowest mark that a student can have and still be awarded a passing grade?
a.
b.
c.
d.
62
57
44
40
24. A stemplot of a set of data is roughly symmetric, but the data do not even
approximately follow the 68-95-99.7 rule. We conclude that the data are
a.
b.
c.
d.
normal, but they are not standard normal.
standard normal.
not normal.
normal.
25.
Chocolate bars produced by a certain machine are labeled as 8.0 oz.
The
distribution of the actual weights of these chocolate bars is normal with a mean of
8.1 oz. and a standard deviation of 0.1 oz. The proportion of chocolate bars with
weights between 8.2 and 8.3 oz. is
a.
b.
c.
d.
0.819.
0.636.
0.477.
0.136.
Answers:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
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25
A
B
A
B
A
B
D
B
B
D
C
D
B
B
B
C
B
C
B
C
C
C
C
C
D