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) 5 b) 10 c) 30 d) 128
2) The percentage of students with more than $10.00 but less than $30.00 is closest to a) 20% b) 46% c) 63% d) 88%
3) The third quartile for this distribution occurs in which class interval? a) 10-20 b) 20-30 c) 30-40 d) 40-50
4) 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) to the right of the median
b) to the left of the median
c) the same as the median
d) 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). Use these box plots to answer questions 6 - 7.
6) Which group has a greater proportion of its observations below a pulse rate of
82? a) group 1 b) group 2 c) they would be about the same d) not enough information
7) Approximately 25% of the students in group 1 had a pulse rate above: d) 106
8) Three randomly selected students had quiz scores of -4, 5, and 8. The
. standard deviation for this sample is: a) 58 b) 76 c) 88 a) 0 b) 6.245 c) 16.667 d) 39.000
9) In the early part of the 20 th 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) Church leaders were encouraging their members to commit crimes. b) Both crimes and Church membership increased as the population increased. c) Crime rate is a lurking variable.
d) Church membership is a lurking variable.
10) Which of the following statements is true:
a) the mean of a sample is always greater than the std. dev. of the sample.
b) the std. dev. for a data set with 3 observations must always be positive.
c) the 3Q of a data set must always be greater than the 1Q of the data set.
c) 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) no units -- the standard deviation is just a number b) grams squared c) milligrams d) 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 2 4 8 9 9
6 0 3 5 6 7 7 8 9
7 3 4 7 8 9 9
8
9 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.
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 b.
25
20
15
10
5
France Germany Italy Japan Sweden U.S.
France Germany Italy Japan Sweden U.S.
c.
20
15
10
5
France Germany Italy Japan Sweden U.S.
d.
20
15
10
5
France Germany Italy Japan Sweden U.S.

16 . The five-number summary of a set of data
a. is the mean, standard deviation, first quartile, median, and third quartile. b. is the mean, median, mode, variance, and standard deviation. c. can be computed from the information in a stemplot. d. is the 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. exactly $38,000. b. larger than $38,000. c. smaller than $38,000. d. above $41,000.
Use the following density curve to answer questions 18 – 20.
18 . For this density curve, the third quartile is
a. 0.5. b. 0.75. c. 1.5. d. 1.75.
19 . For this density curve, what percent of the observations lie between 0.25 and
0.50?
a. 0.25% b. 12.5% c. 25% d. 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. 2.5% b. 5% c. 16% d. 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. 32% b. 5% c. 2.5% d. 0.0015%

22 . Using the standard normal distribution tables, what is the area under the standard normal curve corresponding to Z < 1.15?
a. 0.1357 b. 0.8643 c. 0.8749 d. 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. 62 b. 57 c. 44 d. 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. normal, but they are not standard normal. b. standard normal. c. not normal. d. 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. 0.819. b. 0.636. c. 0.477.
d. 0.136.
Answers:
1 A
2 B
3 A
4 B
5 A
6 B
7 D
8 B
9 B
10 D
11 C
12 D
13 B
14 B
15 B
16 C
17 B
18 C
19 B
20 C
21 C
22 C
23 C
24 C
25 D