ANSWER ALL 25 QUESTIONS BA3006789SP2013 Multiple Choice Identify the choice that
ID: 3054680 • Letter: A
Question
ANSWER ALL 25 QUESTIONS
BA3006789SP2013
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____ 1. A continuous random variable is uniformly distributed between a and b. The probability density function between a and b is
a.
zero
c.
(b ? a)
b.
(a ? b)
d.
1/(b ? a)
____ 2. The assembly time for a product is uniformly distributed between 6 to 10 minutes. The standard deviation of assembly time (in minutes) is approximately
a.
0.3333
b.
0.1334
c.
16
d.
None of the alternative answers is correct.
____ 3. A normal probability distribution
a.
is a continuous probability distribution
c.
can be either continuous or discrete
b.
is a discrete probability distribution
d.
always has a standard deviation of 1
____ 4. The highest point of a normal curve occurs at
a.
one standard deviation to the right of the mean
b.
two standard deviations to the right of the mean
c.
approximately three standard deviations to the right of the mean
d.
the mean
____ 5. Z is a standard normal random variable. The P(-1.96 ? z ? -1.4) equals
a.
0.8942
c.
0.475
b.
0.0558
d.
0.4192
____ 6. Given that z is a standard normal random variable, what is the value of z if the area to the right of z is 0.1112?
a.
0.3888
c.
2.22
b.
1.22
d.
3.22
____ 7. Z is a standard normal random variable. What is the value of z if the area between -z and z is 0.754?
a.
0.377
c.
2.16
b.
0.123
d.
1.16
____ 8. Excel's NORM.DIST function can be used to compute
a.
cumulative probabilities for a standard normal z value
b.
the standard normal z value given a cumulative probability
c.
cumulative probabilities for a normally distributed x value
d.
the normally distributed x value given a cumulative probability
____ 9. Excel's NORM.INV function can be used to compute
a.
cumulative probabilities for a standard normal z value
b.
the standard normal z value given a cumulative probability
c.
cumulative probabilities for a normally distributed x value
d.
the normally distributed x value given a cumulative probability
____ 10. The exponential probability distribution is used with
a.
a discrete random variable
b.
a continuous random variable
c.
any probability distribution with an exponential term
d.
an approximation of the binomial probability distribution
____ 11. Excel's EXPON.DIST function can be used to compute
a.
exponents
b.
exponential probabilities
c.
cumulative exponential probabilities
d.
Both exponential probabilities and cumulative exponential probabilities are correct.
Exhibit 6-2
The travel time for a college student traveling between her home and her college is uniformly distributed between 40 and 90 minutes.
____ 12. Refer to Exhibit 6-2. What is the random variable in this experiment?
a.
the uniform distribution
c.
90 minutes
b.
40 minutes
d.
the travel time
Exhibit 6-6
The life expectancy of a particular brand of tire is normally distributed with a mean of 40,000 and a standard deviation of 5,000 miles.
____ 13. Refer to Exhibit 6-6. What is the probability that a randomly selected tire will have a life of at least 47,500 miles?
a.
0.4332
b.
0.9332
c.
0.0668
d.
None of the alternative answers is correct.
____ 14. A probability distribution for all possible values of a sample statistic is known as a
a.
sample statistic
c.
simple random sample
b.
parameter
d.
sampling distribution
____ 15. Doubling the size of the sample will
a.
reduce the standard error of the mean to one-half its current value
b.
reduce the standard error of the mean to approximately 70% of its current value
c.
have no effect on the standard error of the mean
d.
double the standard error of the mean
____ 16. A sample of 24 observations is taken from a population that has 150 elements. The sampling distribution of is
a.
approximately normal because is always approximately normally distributed
b.
approximately normal because the sample size is large in comparison to the population size
c.
approximately normal because of the central limit theorem
d.
normal if the population is normally distributed
Exhibit 7-3
The following information was collected from a simple random sample of a population.
16
19
18
17
20
18
____ 17. Refer to Exhibit 7-3. The point estimate of the mean of the population is
a.
18.0
b.
19.6
c.
108
d.
sixteen, since 16 is the smallest value in the sample
____ 18. An interval estimate is used to estimate
a.
the shape of the population's distribution
c.
a sample statistic
b.
the sampling distribution
d.
a population parameter
____ 19. If we want to provide a 95% confidence interval for the mean of a population, the confidence coefficient is
a.
0.485
c.
0.95
b.
1.96
d.
1.645
Exhibit 8-3
A random sample of 81 automobiles traveling on a section of an interstate showed an average speed of 60 mph. The distribution of speeds of all cars on this section of highway is normally distributed, with a standard deviation of 13.5 mph.
____ 20. Refer to Exhibit 8-3. The value to use for the standard error of the mean is
a.
13.5
c.
2.26
b.
9
d.
1.5
____ 21. Which of the following hypotheses applies to a situation where action must be taken both when H0 cannot be rejected and when H0 can be rejected?
a.
c.
b.
d.
____ 22. In tests about a population proportion, p0 represents the
a.
hypothesized population proportion
c.
observed p-value
b.
observed sample proportion
d.
probability of
____ 23. In hypothesis testing if the null hypothesis has been rejected when the alternative hypothesis has been true,
a.
a Type I error has been committed
b.
a Type II error has been committed
c.
either a Type I or Type II error has been committed
d.
the correct decision has been made
____ 24. The level of significance can be any
a.
negative value
c.
value larger than 0.1
b.
value
d.
None of the answers is correct.
Exhibit 9-6
A random sample of 100 people was taken. Eighty of the people in the sample favored Candidate A. We are interested in determining whether or not the proportion of the population in favor of Candidate A is significantly more than 75%.
____ 25. Refer to Exhibit 9-6. The p-value is
a.
0.2112
c.
0.025
b.
0.05
d.
0.0156
a.
zero
c.
(b ? a)
b.
(a ? b)
d.
1/(b ? a)
Explanation / Answer
Solution:-
1. option d. 1/(b-a)
2. option d. None of the alternative answers is correct.
=>sqrt((b-a)^2/(12)) = sqrt((10-6)^2/(12)) =1.1547
3. option a. is a continuous probability distribution
4. option d. the mean
5. option b. 0.0558
=> P (?1.96 < Z < ?1.4) = 0.0558
6. option b. 1.22
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