1.
A.
B.
C.
D.
If the variance is 3.6 grams, what is the standard deviation?
0.6
1.897
6.0
12.96
2.
Sixty percent of the customers of a fast food chain order a hamburger,
french fries and a drink. If arandom sample of 15 cash register receipts is
selected, what is the probability that 10 or more will showthat the above
three food items were ordered?
A.
1.000
B.
0.186
C.
0.403
D.
0.000
3.
Judging from recent experience, 5 percent of the computer keyboards
produced by an automatic,high-speed machine are defective. If six
keyboards are randomly selected, what is the probability thatnone of the
keyboards are defective?
A.
0.001
B.
0.167
C.
0.735
D.
0.500
4.
The probabilities and the number of automobiles lined up at a
Lakeside Olds at opening time (7:30a.m.) for service are
Number
Probability
1
0.05
2
0.30
3
0.40
4
0.25
On a typical day, how many automobiles should Lakeside Olds expect to be
lined up at opening?
A.
10.00
B.
1.00
C.
2.85
D.
1.96
5.
On a very hot summer day, 5 percent of the production employees at
Midland States Steel are absentfrom work. The production employees are
randomly selected for a special in-depth study onabsenteeism. What is the
probability of randomly selecting 10 production employees on a hot summer
day and finding that none of them are absent?
A.
0.002
B.
0.344
C.
0.599
D.
0.100
6.
Which one of the following is NOT a condition of the binomial
distribution?
A.
Independent trials
B.
Only two outcomes
C.
Probability of success remains constant from trial to trial
D.
At least 10 observations
7.
The weight of an offensive linesman may be 205.15 pounds, 210.23
pounds, 225.05 pounds or 219.14pounds. What is this an illustration of?
A.
Continuous random variable
B.
Discrete random variable
C.
Complement rule
D.
All of the above
8.
A true-false test consists of six questions. If you guess the answer to
each question, what is theprobability of getting all six questions correct?
A.
0
B.
0.016
C.
0.062
D.
0.250
9.
What is the following table called?
Number of Heads Probability of Outcome
0
1/8 = 0.125
1
3/8 = 0.375
2
3/8 = 0.375
3
1/8 = 0.125
A.
Probability distribution
B.
C.
D.
Cumulative frequency distribution
Standard deviation
Frequency table
10. Which of the following is NOT a characteristic of a binomial probability
distribution?
A.
Each outcome is mutually exclusive
B.
Each trial is independent
C.
Probability of success remains constant from trial to trial
D.
Each outcome results from two trials
E.
All of the above are characteristics of the binomial distribution
11.The upper and lower limits of a uniform probability distribution are
A.
Positive and negative infinity.
B.Plus and minus three standard
deviations.
C. O and 1.
D. The maximum and minimum values of the random variable.
12. For a standard normal distribution, what is the probability that z is greater
than 1.75?
A.
0.0401
B. 0.0459
C. 0.4599
D.
0.9599
13. What is the area under the normal curve between z = -1.0 and z = -2.0?
A.
0.0228
B. 0.3413
C. 0.1359
D.
0.4772
14. The mean amount spent by a family of four on food per month is $500 with
a standard deviation of$75. Assuming that the food costs are normally distributed,
what is the probability that a family spendsless than $410 per month?
A.
0.2158
B. 0.8750
C. 0.0362
D.
0.1151
15. The mean score of a college entrance test is 500; the standard deviation
is 75. The scores arenormally distributed. What percent of the students scored
below 320?
A.
B.
About 50.82%
About 34.13%
C.
D.
About 7.86%
About 0.82%
16. A new extended-life light bulb has an average service life of 750 hours,
with a standard deviation of 50 hours. If the service life of these light bulbs
approximates a normal distribution, about what percent of the distribution will be
between 600 hours and 900 hours?
A.
95%
B.68%
C.34%
D.
99.7%
17. Which of the following is true in a normal distribution?
A. Mean equals the mode and the median
B.Mode equals the median
C.Mean divides the distribution into two equal parts
D. All of the above are correct
18. Two normal distributions are compared. One has a mean of 10 and a standard
deviation of 10. The second normal distribution has a mean of 10 and a standard
deviation of 2. Which of the following is true?
A.
B.
C.
D.
The locations of the distributions are different
The distributions are from two different families of distributions
The dispersions of the distributions are different
The dispersions of the distributions are the same
19. In an illustration of a normal probability distribution, a shaded area represents
A.
a permutation
B.
a combination
C.
a probability
D.
a standard deviation
20.The weekly mean income of a group of executives is $1000 and the standard
deviation of this groupis $100. The distribution is normal. What percent of the
executives have an income of $925 or less?
A.
About 15%
B.
About 85%
C.
About 50%
D.
About 23%
21.What is the difference between a sample mean and the population mean called?
A.
Standard error of the mean
B.
Sampling error
C.
Interval estimate
D.
Point estimate
22.The true sampling error is usually not known because
A.
B.
C
D.
u. is a unknown
u. is a random variable
2
σ is unknown
The sample mean cannot be computed
23.A marketing firm is studying consumer preferences for winter fashions in four
different months.From a population of women, 18-21 years of age, a random
sample of 100 women was selected inJanuary. Another random sample of 100
women was selected in March. Another random sample of 100women was
selected in June. Another random sample of 100 women was selected in
September.
A.
The sample size was 4.
B.
The sample size was 100.
C.
The sample size was 400.
D.
The sample size was 1.
24. Manufacturers were subdivided into groups by volume of sales. Those with
more than $100 millionin sales were classified as Class A large; those from $50 to
$100 million as Class A medium size; andthose between $25 and $50 million..., and
so on. Samples were then selected from each of thesegroups. What is this type of
sampling called?
A.
Simple random
B.
Stratified random
C.
Cluster
D.
Systematic
25. The mean weight of trucks traveling on a particular section of 1-475 is not
known. A state highwayinspector needs an estimate of the mean. He selects a
random sample of 49 trucks passing the weighingstation and finds the mean is 15.8
tons, with a standard deviation of the sample of 4.2 tons. What isprobability that a
truck will weigh less than 14.3 tons?
A.
0.0062
B. 0.3632
C.0.1368
D.
0.4938
26. Mileage tests were conducted on a randomly selected sample of 100 newly
developed automobiletires. The average tread wear was found to be 50,000 miles
with a standard deviation of 3,500 miles.What is the best estimate of the average
tread life in miles for the entire population of these tires?
A.
50,000
B.
3,500
C.
(50,000/100)
D.
(3,500/100)
27. An accounting firm is planning for the next tax preparation season. From
last year's returns, the firm collects a systematic random sample of 100 filings. The
100 filings showed an average preparation time of 90 minutes with a standard
deviation of 140 minutes. What is the probability that the meancompletion time
will be more than 120 minutes?
A.
Approximately zero
B.
0.0832
C.
0.4168
D.
0.0162
28. A group of statistics students decided to conduct a survey at their university
to find the average(mean) amount of time students spend studying per week. Based
on a simple random sample, theysurveyed 144 students. The statistics showed that
students studied an average of 20 hours per weekwith a standard deviation of 10
hours. What is the probability of finding a sample mean less than 18hours?
A.
0.4820
B.
0.4920
C.
0.0080
D.
0,0180
29. The Intelligence Quotient (IQ) test scores are normally distributed with a
mean of 100 and astandard deviation of 15. What is the probability that a person
would score 130 or more on the test?
A.
0.0228
B. 0.9772
C. 0.4772
D.
0.9544
30. Truck tire life is normally distributed with a mean of 60,000 miles and a
standard deviation of 4,000miles. What is the probability that a tire will last 72,000
miles or more?
A.
0.0013
B. 0.9987
C. 0.4987
D.
0.9544
31. The mean number of travel days per year for salespeople employed by
hardware distributors needsto be estimated with a 0.90 degree of confidence. For a
small pilot study the mean was 150 days and thestandard deviation was 14 days. If
the population mean is estimated within two days, how many salespeople should
be sampled?
A.134
B.
452
C.511
D
2100
32. The mean weight of trucks traveling on a particular section of 1-475 is not
known. A state highwayinspector needs an estimate of the mean. He selects a
random sample of 49 trucks passing the weighingstation and finds the mean weight
is 15.8 tons. The population standard deviation is 3.8 tons. What is the 95 percent
interval for the population mean?
A.
14.7 and 16.9
B.13.2 and 17.6
C.10.0 and 20.0
D.
16.1 and 18.1
33. A bank wishes to estimate the mean credit card balance owed by its
customers. The populationstandard deviation is estimated to be $300. If a 98
percent confidence interval is used and an interval of$75 is desired, how many
customers should be sampled?
A.
44
B.
212
C.
629
D.
87
34. For a given confidence interval, what is the interpretation of a 96%
confidence level?
A.
96% chance that the given interval includes the true value of the population
parameter
B.
Approximately 96 out of 100 such intervals would include the true value of
the population parameter
C.
4% chance that the given interval does not include the true value of the
population parameter
D.
Both a and c are true
35.
A.
B.
C.
D.
How is the t distribution similar to the standard z distribution?
Both are continuous distribution
Both are bell-shaped
Both are families of distributions
A and B
36.
A.
B.
C.
D.
A sample mean is the best point estimate of the
population standard deviation
population median
population mean
the sample standard deviation
37.
A.
B.
C.
D.
A 95% confidence interval infers that the population mean
is between 0 and 100%
is within ±1.96 standard deviations of the sample mean
is within ±1.96 standard errors of the sample mean
is too large
38.
A.
B.
C.
D.
The distribution of Student's t is
symmetrical
negatively skewed
positively skewed
a discrete probability distribution
39. A local retail company wants to estimate the mean amount spent.
Their budget limits the number ofsurveys to 225. What is their maximum
error of the estimated mean amount spent for a 99% level ofconfidence and
an estimated standard deviation of $10.00?
A.
$10
B.
$1.00
C.
1%
D.
$1.72
40. Recently, a university surveyed recent graduates of the English
Department for their startingsalaries. Four hundred graduates returned the
survey. The average salary was $25,000 with a standarddeviation of $2,500.
A 95% confidence interval is constructed. What does the confidence interval
mean?
A.
The population mean is in the interval
B.
The population mean is not in the interval
C.
The likelihood that any confidence interval based on a sample of 400
graduates will contain thepopulation mean is 0.95
D.
There is a 5% chance that the computed interval does not contain the
population mean
41.
A.
B.
C.
D.
What is the level of significance?
Probability of a Type II error
Probability of a Type I error
z-value of 1.96
Beta error
42. A machine is set to fill the small size packages of M&M candies with
56 candies per bag. A samplerevealed: 3 bags of 56, 2 bags of 57,1 bag of
55, and 2 bags of 58. How many degrees of freedom arethere?
A.
9
B.
1
C.
8
D.
7
43.
A.
B.
C.
D.
What is a Type II error?
Accepting a false null hypothesis
Rejecting a false null hypothesis
Accepting a false alternate hypothesis
Rejecting a false alternate hypothesis
44.
A.
B.
C.
D.
What is another name for the alternate hypothesis?
Null hypothesis
Hypothesis of no difference
Rejected hypothesis
Research hypothesis
45. What is the probability of making a Type II error if the null hypothesis
is actually true?
A. α
B. 1
C. O
D. 0.05
46.
risk?
A.
B.
C.
D.
E.
If we reject the null hypothesis what can we conclude subject to the a
Null hypothesis is false
Alternative hypothesis is false
Null hypothesis is true
Both the null hypothesis and the alternative hypothesis are true
Both the null hypothesis and the alternative hypothesis are false
47. If 20 out of 50 students sampled live in a college dormitory, what is
the estimated proportion ofstudents at the University living in a dormitory?
A.
0.20
B.
0.40
C.
D.
0.50
0.60
48. Based on the Nielsen ratings, the local CBS affiliate claims its 11:00
PM newscast reaches 41% of theviewing audience in the area. In a survey of
100 viewers, 36% indicated that they watch the late eveningnews on this
local CBS station. What is the null hypothesis?
A. π = .36
B. π =0.41
C. π 0.36
D.
μ =0.41
49. It is claimed that in a bushel of peaches less than ten percent are
defective. A sample of 400 peachesis examined and 50 are found to be
defective. What is the null hypothesis?
A.
π 0.10
B.
π 0.10
C.
D.
π
π
0.10
= 0.10
50. It is claimed that in a bushel of peaches less than ten percent are
defective. A sample of 400 peachesis examined and 50 are found to be
defective. If a = 0.025, what will be the decision?
A.
Fail to reject the null and conclude the defects are not greater than
10%
B.
Reject the null and conclude the defects are not greater than 10%
C.
Reject the null and conclude the defects are greater than 10%
D.
Fail to reject the null and conclude the defects are not less than 10%
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