Stat quiz 2 solution correct answers

Stat quiz 2 solution correct answers

01. A probability is a number p such that:

A. 0 < p < 1
B. 0 ≤ p ≤ 1
C. -1 < p < 1
D. -1 ≤ p ≤ 1
E. None of the above

02. The Complement rule states that the probability of an event not occurring is

A. equal to one minus the probability it will occur. 
B. equal to one minus the probability it will not occur. 
C. equal to 0.0
D.  equal to 1.0
E. None of the above

03. A tire manufacturer claims that the probability of its XLT tire lasting 50,000 miles or more is 0.80. If three XLT tires are installed on a car what is the probability that all three will last 50,000 miles or more?

A. 0.800.
B. 0.640.
C. 0.240.
D. 0.512. 
E. None of the above 

04. In how many different ways can a work party of 4 be chosen from 9 volunteers?

A. 4 
B. 36
C. 126 
D. 3024
E. None of the above 

05. Which of the following is/are properties of the Binomial Distribution?

A. The number of trials is fixed in advance.
B. The trials are independent.
C. Each trial has exactly two outcomes.
D. The probability of success is the same for each trial.
E. All of the above.

06. A fair coin is tossed 6 times. What is the probability of getting exactly 3 heads in the 6 tosses?

A. 0.2
B. 0.3
C. 0.4
D. 0.5
E. None of the above 

07. The mean of a probability distribution is referred to as the 

A. median
B. mode
C. expected value
D. weighted mean
E. none of the above

08. The number of armed robberies and their probabilities, in a particular city in a month, are given in the table below: 

Number of armed robberies

Probability

1

0.05

2

0.30

3

0.40

4

0.25

How many armed robberies on the average should be expected on a typical month?

A. 10.00
B. 2.50
C. 2.85
D. 3.01
E. None of the above 

09. A recent survey of local cell phone retailers showed that of all cell phones sold last month, 64% had a camera, 28% had a music player and 22% had both. The probability that a cell phone sold last month had a camera or a music player is

A. 0.92
B. 0.70
C. 0.18
D. 0.36
E. None of the above 

10. The probability of two events occurring together is referred to as 

A. a marginal probability
B. a conditional probability
C. a subjective probability
D. the multiplication rule
E. a joint probability 

11. A student’s score on a test is 110. The scores are normally distributed with mean µ = 120 and standard deviation σ = 8. Find the student’s z-score.

A. 1.25
B. -1.25
C.  -1.52
D. 0.25
E. None of the above

12. To construct a normal distribution, the measurements needed are

A. the mean and the median
B. the mode and the standard deviation
C. the median and the standard deviation
D. the standard deviation and the variance
E. none of the above

13. Which of the following is not a property of the standard normal distribution?
A. It is continuous
B. It is uniform 
C. It is bell-shaped
D. It is unimodal
E. The curve never touches the horizontal axis.

14. Consider the Standard Normal distribution. Find P(-0.73 < z < 2.21)

A. -0.7537
B. 0.9987
C. 0.7534 
D. 0.7537
E. none of the above

15. Consider the Standard Normal distribution. Find the probability P(z > 0.59)

A 0.7224
B 0.2190
C 0.2224
D 0.2776
E None of the above 

16. Consider the Standard Normal distribution. Find the probability that z is less than -1.82.

A. 0.0351
B. -0.0344
C. 0.0344 
C.0.9656 
E. none of the above

17. Find the value of z such that the area to the left of z is 9% of the total area under the curve.

A. 0.82
B. -0.82
C.  1.34
D. -1.34
E. none of the above

18. Find the value of z such that the area to the right of z is 67% of the total area under the standard normal curve.

A 0.44
B -0.44
C 1.00
D -1.50
E None of the above

19.  Find the value of z such that the area between –z and +z is 98% of the total area under the standard normal curve.
A. 2.02
B. 1.96
C. 

Correct answer 2.33 (to be precise 2.326)