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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## This question was asked on Feb 25, 2011 and answered on Mar 01, 2011.

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