Department of Economics
SS2J03: (Introductory Statistics)
Term Test 2, March 21st, 2018
Instructor: Rizwan Tahir Time Allowed: 60 minutes
Instructions: Please read these BEFORE BEGINNING the exam.
35 Multiple Choice Questions (35 Marks)
Both the Scranton sheet and the test must be turned in when you are finished with
1. BE SURE TO WRITE YOUR NAME, STUDENT ID ON THE SCRANTON SHEET AND
THE FRONT PAGE OF THIS EXAM
2. Calculators are permitted during the exam.
1) The binomial probability distribution is right-skewed if:
A) p is 0.25 or smaller *B) p is less than 0.50
C) p is equal to 0.50 D) p is greater than 0.50
2) A small class has 10 students. Seven of the students are male and three are
female. You write the name of each student on a small card. The cards are shuffled
thoroughly, and you choose one at random, observe the name of the student, and
replace it in the set. The cards are thoroughly reshuffled, and you again choose a card at
random, observe the name, and replace it in the set. This is done a total of five times. Let
X be the number of cards observed in these trials with a name corresponding to a
female student. The random variable X has which probability distribution?
A) the Normal distribution, with mean 3 and variance 1
*B) the binomial distribution, with parameters n = 5 and p = 0.3
C) the binomial distribution, with parameters n = 5 and p = 0.7
D) None of the above
3) A college basketball player makes 70% of his free throws. At the end of a game,
his team is losing by two points. He is fouled attempting a three-point shot and is
awarded three free throws. Assuming each free throw is independent, what is the
probability that he makes at least two of the free throws?
*A) 0.784 B) 0.700 C) 0.441 D) 0.216
4) A recent article in the paper claims that business ethics are at an all-time low.
Reporting on a recent sample, the paper claims that 41% of all employees believe their
company president possesses low ethical standards. Assume that responses were
randomly and independently collected. A president of a local company that employs
1,000 people does not believe the paper's claim applies to her company. If the claim is
true, how many of her company's employees believe that she possesses low ethical
*A) 410 B) 959 C) 590 D) 41
5) A campus program evenly enrolls undergraduate and graduate students. If a
random sample of 4 students is selected from the program to be interviewed about the
introduction of a new fast food outlet on the ground floor of the campus building, what
is the probability that all 4 students selected are undergraduate students?
A) 1.00 B) 0.0256 *C) 0.0625 D) 0.16
8) A recent study suggested that 70% of all eligible voters will vote in the next
presidential election. Suppose 20 eligible voters were randomly selected from the
population of all eligible voters. Use a binomial probability table to find the probability
that more than 10 but fewer than 16 of the 20 eligible voters sampled will vote in the
next presidential election.
A) 0.649 B) 0.780 *C) 0.714 D) 0.845
9) According to a published study, 1 in every 9 men has been involved in a minor traffic
accident. Suppose we have randomly and independently sampled twenty-five men and
asked each whether he has been involved in a minor traffic accident. How many of the
25 men do we expect to have never been involved in a minor traffic accident? Round to
the nearest whole number.
A) 9 B) 3 C) 25 *D) 22
10) recent survey found that 73% of all adults over 50 wear glasses for driving. In a
random sample of 80 adults over 50, what is the mean and standard deviation of the
number who wear glasses? Round to the nearest hundredth when necessary.
A) mean: 58.4; standard deviation: 7.64 *B) mean: 58.4; standard deviation: 3.97
C) mean: 21.6; standard deviation: 3.97 D) mean: 21.6; standard deviation: 7.64
11) If we know that the length of time it takes a college student to find a parking spot in
the library parking lot follows a normal distribution with a mean of 3.5 minutes and a
standard deviation of 1 minute, find the probability that a randomly selected college
student will find a parking spot in the library parking lot in less than 3 minutes.
A) 0.1915 B) 0.3551 C) 0.2674 *D) 0.3085
12) Which of the following about the normal distribution is not true?
A) About 2/3 of the observations fall within ±1 standard deviation from the mean.
B) Its parameters are the mean, μ, and standard deviation, .
C) Theoretically, the mean, median, and mode are the same.
*D) It is a discrete probability distribution.
13) For a normal distribution, the z value for an x value that is to the right of the
mean is always:
A) equal to zero B) negative C) greater than 1 *D) positive