Statistics Multiple choice

The Exhibits are the sentences or tables of numbers below the Exhibit
number.

Total 15 multiple choice questions. In the following multiple-choice
questions, circle the correct answer and give 1-3 line defense for your
choice:

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16. If a coin is tossed three times, the likelihood of obtaining three
heads in a row is

a. zero

b. 0.500

c. 0.875

d. 0.125

e. None of the above answers is correct.



17. If A and B are independent events with P(A) = 0.05 and P(B) = 0.65,
then

P(A(B) =

a. 0.05

b. 0.0325

0.65

The following represents the probability distribution for the daily
demand of microcomputers at a local store.

Demand Probability

0 0.1

1 0.2

2 0.3

3 0.2

0.2

Exhibit 5-2

The student body of a large university consists of 60% female students.
A random sample of 8 students is selected.

20. Refer to Exhibit 5-2. What is the probability that among the
students in the sample exactly two are female?

a. 0.0896

b. 0.2936

c. 0.0413

d. 0.0007

e. None of the above answers is correct.



21. Refer to Exhibit 5-2. What is the probability that among the
students in the sample at least 7 are female?

a. 0.1064

b. 0.0896

c. 0.0168

d. 0.8936

None of the above answers is correct.

Exhibit 5-4

Forty percent of all registered voters in a national election are
female. A random sample of 5 voters is selected.

Exhibit 5-4

Forty percent of all registered voters in a national election are
female. A random sample of 5 voters is selected.

27. Refer to Exhibit 5-4. The probability that the sample contains 2
female voters is

a. 0.0778

b. 0.7780

c. 0.5000

d. 0.3456

e. None of the above answers is correct.



28. Refer to Exhibit 5-4. The probability that there are no females in
the sample is

a. 0.0778

b. 0.7780

c. 0.5000

d. 0.3456

e. None of the above answers is correct.

34. Which of the following is not a characteristic of an experiment
where the binomial probability distribution is applicable?

a. the experiment has a sequence of n identical trials

b. exactly two outcomes are possible on each trial

c. the trials are dependent

d. the probabilities of the outcomes do not change from one trial to
another

e. all are characteristics of a binomial probability experiment



35. Which of the following is not a property of a binomial experiment?

a. the experiment consists of a sequence of n identical trials

b. each outcome can be referred to as a success or a failure

c. the probabilities of the two outcomes can change from one trial to
the next

d. the trials are independent

e. All of the above answers are correct.



36. A production process produces 2% defective parts. A sample of five
parts from the production process is selected. What is the probability
that the sample contains exactly two defective parts?

a. 0.0004

b. 0.0038

c. 0.10

d. 0.02

e. 0.00



37. Z is a standard normal random variable. The P(-1.96 ( Z ( -1.4)
equals

a. 0.8942

b. 0.0558

c. 0.475

d. 0.4192

e. None of the above answers is correct.



38. Z is a standard normal random variable. The P(1.20 ( Z ( 1.85)
equals

a. 0.4678

0.3849

c. 0.8527

d. 0.0829

e. None of the above answers is correct.



39. Z is a standard normal random variable. The P (-1.20 ( Z ( 1.50)
equals

a. 0.0483

b. 0.3849

c. 0.4332

d. 0.8181

e. None of the above answers is correct.



40. Z is a standard normal random variable. Compute the following
probability.

P(Z = 2.56)

A sample of five customers is selected. What is the probability that
exactly two customers in the sample will default on their payments?

a. 0.2592

b. 0.0142

c. 0.9588

d. 0.7408

e. 0.0000



31. Twenty percent of the students in a class of 100 are planning to go
to graduate school. The standard deviation of this binomial
distribution is

a. 20

b. 16

c. 4

d. 2

e. None of the above answers is correct.



32. If you are conducting an experiment where the probability of a
success is .02 and you are interested in the probability of 4 successes
in 15 trials, the correct probability function to use is the

a. standard normal probability density function

b. normal probability density function

c. Poisson probability function

d. binomial probability function

e. None of the above answers is correct.

33. Which of the following statements about a discrete random variable
and its probability distribution are true?

a. Values of the random variable can never be negative.

b. Some negative values of f(x) are allowed as long as (f(x) = 1.

c. Values of f(x) must be greater than or equal to zero.

d. The values of f(x) increase to a maximum point and then decrease.

e. None of the above answers is correct.