STAT 3090: Cumulative Review KEY
Multiple Choice. Circle the letter corresponding to the best answer choice.
1. A small college has several professors
... [Show More] in the Chemistry and Biology departments. The number of
years of experience for the professors in the departments are to be compared:
Chemistry | 1 | 1 | 4 | 5 | 8 | 15 | 22
Biology | 0 | 1 | 2 | 5 | 6 | 8 | 17For which of these measurements does the Chemistry department have the larger value?
I. Range
II. Interquartile range
III. Median
(A) I only
(B) II only
(C) III only
(D) I and II only
(E) I, II, and III
2. The following boxplots summarize two data sets, A and B.
Which of the following statements is not justified by the plots?
(A) The median for Set A is less than the median for Set B.
(B) The range for Set A is less than the range for Set B.
(C) The IQR for Set A is less than the IQR for Set B.
(D) The maximum value for Set A is less than the maximum value for Set B.
(E) The sample size for Set A is less than the sample size for Set B.
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3. At a college the scores on the chemistry final exam are approximately normally distributed, with a
mean of 75 and a standard deviation of 12. The scores on the calculus final are also approximately
normally distributed, with a mean of 80 and a standard deviation of 8. A student scored 81 on the
chemistry final and 84 on the calculus final. Relative to the students in each respective class, in
which subject did the student do better?
(A) The student did better in chemistry.
(B) The student did better in calculus.
(C) The student did equally well in each course.
(D) There is no basis for comparison, since the subjects are different from each other and are in
different departments.
(E) There is not enough information for comparison, because the number of students in each
class is not known.
4. The ages of a group of patients being treated at one hospital for osteoporosis are summarized in the
histogram below. Which of the following best describes the shape of the distribution? How will the
mean age compare to the median value?
(A)Skewed right; mean < median
(B) Skewed right; mean > median
(C) Skewed left; mean < median
(D)Skewed left; mean > median
(E) Symmetric; mean = median
5. The variance of the following five numbers: 1, 2, 3, 4, 5 is:
(A) 0
(B) 1.58
(C) 2
(D) 2.5
(E) 10
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6. Suppose that in the United States, 80% of the population owns a cell phone, 60% of the population
owns a digital camera, and 55% of the population owns both a cell phone and a digital camera.
What is the probability that a randomly selected person from the United States owns a cell phone,
given that they own a digital camera?
(A) 0.4800
(B) 0.6875
(C) 0.8000
(D) 0.9167
(E) None of the above
7. Rachel and Ashley are two students in a Statistics class who attend class independently of one
another. For Friday classes, there is a 0.70 probability that Rachel will come to class, while there is a
0.40 probability that Ashley will come to class. For a Friday class, what is the probability that at
least one of them will be there?
(A) 0.28
(B) 0.54
(C) 0.70
(D) 0.82
(E) 1.10
8. Suppose it has been determined that 16% of all homes with refrigerators have Brand A, while 12%
of all homes with refrigerators have Brand B. Also, 2% of homes with refrigerators have both
brands. If one home with a refrigerator is selected at random, what is the approximate probability
that it will have neither Brand A nor Brand B?
(A) 0.26
(B) 0.30
(C) 0.70
(D) 0.74
(E) 0.98
9. Suppose that the probability of event A is 0.4 and the probability of event B is 0.5. What is
P A B ( ) if A and B are mutually exclusive? What is P A B ( ) if A and B are independent?
(A) 0.0, 0.2
(B) 0.0, 0.4
(C) 0.9, 0.2
(D) 0.9, 0.2
(E) Cannot be determined from the information given
10. Which of the following is an example of a discrete random variable?
(A) The time between oil changes in a car.
(B) The time it takes to finish a 60-minute exam.
(C) A person’s height in centimeters.
(D) The number of students passing an exam in a class of 35.
(E) None of the above [Show Less]