Published on 5 Oct 2020

School

Department

Course

Professor

1

McMaster University

Department of Economics

SS2J03: (Introductory Statistics)

Winter 2018,

Term Test 2, March 21st, 2018

Instructor: Rizwan Tahir Time Allowed: 60 minutes

Last Name

KEY

First Name

St. No.

Mac ID

______________@mcmaster.ca

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

the examination.

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.

Max. Marks

Total Score

35

2

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

standards?

*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

6) Canceled

3

7) Canceled

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