RES341 Final Exam - 4 sets of Final exam


Exam : 1
1) A statistician working for the Department of the Interior is constructing a systematic random sample of trees in a forest preserve. All trees have been identified and numbered with a non-invasive number attached to the bark. The statistician wishes to estimate the mean height of the trees in the forest preserve, and has calculated an appropriate sample size of n=43 trees. The 587th of the 731 trees in the preserve was selected as the first observation in the sample. What is the tree number of the second observation in the sample?

A.
.....
588

B.
.....
630

C.
.....
544

D.
.....
604

2) What is the difference between probability sampling and simple random sampling?

A.
.....
Probability sampling is a type of simple random sample.

B.
.....
In probability sampling each item has an identical chance of being chosen.

C.
.....
There is no difference.

D.
.....
Simple random sampling is a type of probability sampling.

3) A poll is planned to determine what proportion of all students favor an increase in fees to support a new track and field stadium. A questionnaire will be published and the first 1000 completed questionnaires will be analyzed. Which of the following errors will be associated with the sample?

A.
.....
Errors due to interviewer bias and selection bias

B.
.....
Sampling errors only

C.
.....
Sampling errors and errors due to selection bias

D.
.....
Only non-sampling errors

4) Which of the following statements is false?

A.
.....
A summary measure calculated from some of the items of interest is a statistic.

B.
.....
Statistical inference is the process of making a prediction based on only a small piece of information.

C.
.....
A summary measure calculated from all items of interest is a parameter.

D.
.....
The main goal of descriptive statistics is to estimate characteristics of populations.

5) Which of the following is not a reason one should have knowledge of statistics?

A.
.....
To make future projections of one’s sales

B.
.....
To be able to mount an effective effort to change a government regulation that negatively affects one’s business

C.
.....
To increase the amount of information available for use

D.
.....
To help interpret existing information

6) Which of the following is not a characteristic of an ideal statistician?

A.
.....
Communicates well (both written and oral)

B.
.....
Can deal with imperfect information

C.
.....
Technically current (e.g. software)

D.
.....
Adapts answers to client desires

7) A supermarket has determined that daily demand for eggs has a bell-shaped distribution, with a mean of 55 cartons and a standard deviation of six cartons. If the supermarket begins each morning with a stock of 61 cartons of eggs, approximately what percentage of days will there be a surplus of eggs?

A.
.....
˜18%

B.
.....
˜84%

C.
.....
˜16%

D.
.....
˜68%

8) A study of the scores on an in plant course in management principles and the years of service of the employees enrolled in the course yielded the following statistics: Test Scores: mean=100 variance = 225 Years of Service: mean=5 variance = 81 Of test scores and years of service, which measure has the greater dispersion?

A.
.....
Years of service

B.
.....
It is impossible to tell.

C.
.....
Test scores

D.
.....
The short-run effects of those changes are always more beneficial to society than are the long-run effects.

9) 
Textbook Price
Number of Textbooks
$25 to $35
2
35 to 45
16
45 to 55
5
55 to 65
7
65 to 75
20
Estimate the mean price of a textbook.

A.
.....
$11.08

B.
.....
$55.40

C.
.....
$554.00

D.
.....
$60.00

10) A multiple-choice test has 20 questions, and there are 4 choices for each question. A student comes to class with four different colored balls of identical shape and size in her pocket. She has decided to draw one ball from her pocket per question and allow the color of the ball to select the answer for each question. What type of probability distribution can be used to figure out her chance of getting 10 questions right?

A.
.....
Poisson distribution

B.
.....
Binomial distribution

C.
.....
Hypergeometric distribution

D.
.....
Normal distribution

11) Which of the following cannot generate a Poisson distribution?

A.
.....
The number of goals in the World Cup soccer game

B.
.....
The number of defects in a new automobile

C.
.....
The number of people at a movie theatre on Friday evening

D.
.....
The number of customers arriving at an ATM in a minute

12) The Information Commons in the main library has 150 personal computers. The probability that any one of them will require repair on a given day is 0.02. To find the probability that exactly 25 of the computers will require repair, one would use what type of probability distribution?

A.
.....
Hypergeometric distribution

B.
.....
Normal distribution

C.
.....
Binomial distribution

D.
.....
Poisson distribution

13) 
The Big Red Arcade and Pizza Palace caters to young teens and sells tokens to play arcade games for 25¢ each and slices of pizza for 50¢ each.  The distribution of sales of pizza slices per customer and sales of arcade tokens per customer is below. 
# Slices of Pizza
0
1
2
3
4
5
Probability
0.05
0.10
0.20
0.30
0.15
0.20

# Arcade Games
0
1
2
3
4
5
Probability
0.01
0.04
0.15
0.20
0.25
0.35
If the expected number of arcade games played by the typical customer is 2 games, what is the standard deviation of the number of arcade games played per customer?

A.
.....
4.43

B.
.....
2.96

C.
.....
1.43

D.
.....
2.10

14) 
The Big Red Arcade and Pizza Palace caters to young teens and sells tokens to play arcade games for 25¢ each and slices of pizza for 50¢ each.  The distribution of sales of pizza slices per customer and sales of arcade tokens per customer is below. 
# Slices of Pizza
0
1
2
3
4
5
Probability
0.05
0.10
0.20
0.30
0.15
0.20
    
# Arcade Games
0
1
2
3
4
5
Probability
0.01
0.04
0.15
0.20
0.25
0.35

What is the total expected per customer revenue for pizza slice sales and arcade token sales?

A.
.....
$1.34

B.
.....
$2.42

C.
.....
$6.69

D.
.....
$2.60

15) 
The Big Red Arcade and Pizza Palace caters to young teens and sells tokens to play arcade games for 25¢ each and slices of pizza for 50¢ each.  The distribution of sales of pizza slices per customer and sales of arcade tokens per customer is below. 
# Slices of Pizza
0
1
2
3
4
5
Probability
0.05
0.10
0.20
0.30
0.15
0.20

# Arcade Games
0
1
2
3
4
5
Probability
0.01
0.04
0.15
0.20
0.25
0.35
What is the probability that revenues from pizza slice sales will be greater than $1.00 per customer?

A.
.....
.43

B.
.....
.85

C.
.....
.95

D.
.....
.65

16) The standard error of the sample mean is equal to 5 when n=25. If the sample size increases by a factor of four, how will the standard error change?

A.
.....
It will quadruple

B.
.....
It will be cut to ¼ of 5

C.
.....
It will double

D.
.....
It will be cut in half

17) The expected value of the sampling distribution of the sample mean equals the population mean

A.
.....
for all populations.

B.
.....
when the population size N > 30.

C.
.....
when the population is normally distributed.

D.
.....
when the population is symmetric.

18) The use of the student’s t distribution requires which of the following assumptions?

A.
.....
The sample is drawn from a positively skewed distribution

B.
.....
The population is normal

C.
.....
The sample size is greater than 30

D.
.....
The population variance is known

19) 
Construct a  95% confidence interval estimate for the difference between the means of two normally distributed populations, where the unknown population variances are assumed not to be equal.  Summary statistics computed from two independent samples are as follows: .....
The upper confidence limit is:

A.
.....
5.788.

B.
.....
24.911.

C.
.....
19.123.

D.
.....
28.212.

20) What does it mean to have 95% confidence in an interval estimate?

A.
.....
In repeated sampling, 95% of the point estimates fall within the given interval.

B.
.....
In repeated sampling, 95% of the population observations fall within the given interval.

C.
.....
In repeated sampling, the population parameter would fall in the given interval 95% of the time.

D.
.....
In repeated sampling, 95% of the intervals would contain the population parameter.

21) Ceteris paribus, which is narrower, a 95% confidence interval with n=100 or a 99% confidence interval with n=30?

A.
.....
Need the margin of error to tell

B.
.....
They are the same width.

C.
.....
The 95% confidence interval

D.
.....
The 99% confidence interval

22) When no point lies outside the control limits of a chart, we conclude that variation in the process is

A.
.....
due to common cause and there is not enough evidence to infer that the process is out of control.

B.
.....
due to common cause and there is enough evidence to infer that the process is out of control.

C.
.....
due to special causes and there is not enough evidence to infer that the process is out of control.

D.
.....
due to special causes and there is enough evidence to infer that the process is under control.

23) To tell if the standard deviation of a process has changed, the control charts used are

A.
.....
S and x bar charts.

B.
.....
R and S charts.

C.
.....
x bar and p charts.

D.
.....
p and R charts.

24) When the results of a process are either defective or acceptable, the charts used for SPC are called

A.
.....
control charts for attributes.

B.
.....
control charts for variables.

C.
.....
control charts for in control process.

D.
.....
control charts for out of control process.

Exam : 2
1) A statistician working for the Department of the Interior is constructing a systematic random sample of trees in a forest preserve. All trees have been identified and numbered with a non-invasive number attached to the bark. The statistician wishes to estimate the mean height of the trees in the forest preserve, and has calculated an appropriate sample size of n=43 trees. The 587th of the 731 trees in the preserve was selected as the first observation in the sample. What is the tree number of the second observation in the sample?

A.
.....
588

B.
.....
630

C.
.....
544

D.
.....
604

2) A poll is planned to determine what proportion of all students favor an increase in fees to support a new track and field stadium. A questionnaire will be published and the first 1000 completed questionnaires will be analyzed. Which of the following errors will be associated with the sample?

A.
.....
Errors due to interviewer bias and selection bias

B.
.....
Sampling errors only

C.
.....
Sampling errors and errors due to selection bias

D.
.....
Only non-sampling errors Cluster sample

3) A survey was mailed to a total of 400 students; 100 were randomly selected from each of the freshman, sophomore, junior and senior classes last semester. What sampling method was used?

A.
.....
Stratified sample

D.
.....
Cluster sample

C
.....
Systematic sample

D
.....
Simple random sample

 

4) The collection and summarization of the socioeconomic and physical characteristics of the employees of a particular firm is an example of

A.

Inferential statistics

B.

descriptive statistics.

C.

a statistics

D.

a parameter

5) Which of the following is not a reason one should have knowledge of statistics?

A

To make future projections of one’s sales

B

To be able to mount an effective effort to change a government regulation that negatively affects one’s business


C

To help interpret existing information


D.

To increase the amount of information available for use

6) Which of the following is an example of statistical inference?


A

C. Counting the number of patients who file malpractice suits after being discharged from hospitals in New York State.


B

B. Calculating the mean age of patients discharged from hospitals in New York State in 1997.


C.

Calculating the amount of fly spray needed for your orchard next season.


D

A. Calculating the mean number of fruit trees damaged by Mediterranean fruit flies in California last year.
Textbook Price
Number of Textbooks
$25 to $35
2
35 to 45
16
45 to 55
5
55 to 65
7
65 to 75
20





Estimate the standard deviation of the price of a textbook.

A.

14.03

B

729.00

C

33.85

D

196.78

8) A study of the scores on an in plant course in management principles and the years of service of the employees enrolled in the course yielded the following statistics: Test Scores: mean=100 variance = 225 Years of Service: mean=5 variance = 81 Of test scores and years of service, which measure has the greater dispersion?

A

The short-run effects of those changes are always more beneficial to society than are the long-run effects.

B

Test scores

C.

Years of service

D

It is impossible to tell.

9) The average score for a class of 30 students was 75. The 20 male students in the class averaged 70. The 10 female students in the class averaged

A.

85

B

70

C

75

D

80
10) The Information Commons in the main library has 150 personal computers. The probability that any one of them will require repair on a given day is 0.02. To find the probability that exactly 25 of the computers will require repair, one would use what type of probability distribution?
A.
.....
Hypergeometric distribution
A.
B.
.....
Normal distribution
B.
C.
.....
Binomial distribution
C.
D.
.....
Poisson distribution
D.

11) The local police department must write, on average, 5 tickets a day to keep department revenues at budgeted levels. Suppose the number of tickets written per day follows a Poisson distribution with a mean of 5.5 tickets per day. Interpret the value of the mean.

A

The number of tickets written most often is 5.5 tickets per day

B.

If we sampled all days, the arithmetic average or expected number of tickets written would be 5.5 tickets per day.

C

 Half of the days have less than 5.5 tickets written and half of the days have more than 5.5 tickets written

D

The mean cannot be interpreted.

12) Which of the following is a characteristic of every binomial distribution?

A

The probability of success increases from trial to trial.

B.

Each outcome is mutually exclusive.

C

The outcome of a trial depends on the number of trials.

D

Each outcome is dependent on the previous outcome.

13) Past history shows that 70% of college students prefer Pepsi. Groups of nine students are selected. Describe the histogram that would represent this distribution. The histogram would be:

A.
left-skewed with ten columns.

B

right-skewed with ten columns.

C

left-skewed with nine columns.

D

right-skewed with nine columns.

14) 
The Big Red Arcade and Pizza Palace caters to young teens and sells tokens to play arcade games for 25¢ each and slices of pizza for 50¢ each.  The distribution of sales of pizza slices per customer and sales of arcade tokens per customer is below. 
# Slices of Pizza
0
1
2
3
4
5
Probability
0.05
0.10
0.20
0.30
0.15
0.20

# Arcade Games
0
1
2
3
4
5
Probability
0.01
0.04
0.15
0.20
0.25
0.35
What is the probability that revenues from pizza slice sales will be greater than $1.00 per customer?

A

43

B

85

C.

.65

D

95


15) Which of these parameters associated with a binomial experiment will produce a probability distribution with the smallest standard deviation; given n is the same for each situation?

A

p = 0.5

B

p = 0.4

C

p = 0.3

D.

(1- p) = 0.1.
16) The expected value of the sampling distribution of the sample mean equals the population mean

A.
.....
for all populations.

B.
.....
when the population size N > 30.

C.
.....
when the population is normally distributed.

D.
.....
when the population is symmetric.

17) The use of the student’s t distribution requires which of the following assumptions?

A.
.....
The sample is drawn from a positively skewed distribution

B.
.....
The population is normal

C.
.....
The sample size is greater than 30

D.
.....
The population variance is known

18) A random variable follows the student’s t distribution. The probability that it will be positive is

A
less than 0.50.

B.
0.5

C.
0

D.
1

19) 
A study of 200 insomniacs paid for by the Serta Mattress Company found that the average insomniac counted 350 sheep before falling asleep, with a standard deviation of 120.  An insomniac is a person who has difficulty falling asleep.  Some useful numbers might be:
=NORMSINV(0.89)
1.2265
=NORMSINV(0.945)
1.5982
=TINV(0.89,199)
0.1385
=TINV(0.11,199)
1.6053
=TINV(0.055,199)
1.9302         
Out of the 200 insomniacs, 98 reported regularly watching The Late Show with David Letterman before they began to count sheep. Calculate the margin of error for a 78% confidence interval of the true proportion of insomniacs who regularly watch David Letterman before counting sheep.

A

0.056

B

0.136

C

0.164

D

0.043

20) 
Construct a  95% confidence interval estimate for the difference between the means of two normally distributed populations, where the unknown population variances are assumed not to be equal.  Summary statistics computed from two independent samples are as follows:  
The upper confidence limit is:

A

24.911

B

28.212.

C

5.788

D

19.123

21) Ceteris paribus, which is narrower, a 95% confidence interval with n=100 or a 99% confidence interval with n=30?

A

The 99% confidence interval

B

Need the margin of error to tell

C

They are the same width

D

The 95% confidence interval
22) When the only sources of variation in a production process are caused by chance, the process is said to be


under control.

B

Out of control but in balance

C

Out of balance but under control

D

Out of control

23) In statistical process control, a Type I error occurs if we decide that the process is

A

under control when it is out of control.


out of control when it is under control.

C

out of control when it is out of control.

D

under control when it is under control.

24) When a change has occurred in the mean of the process distribution, the result is referred to as

A

a level shift.

B

A trend

C
 
A cycle



D

instability


Exam : 3
1) When testing for differences between two means, the Behrens-Fisher problem arises when the sample populations are
A. are normal with unequal variances.
B. normal with equal variances.
C. are non-normal and have equal variances.
D. are non-normal and have unequal variances.

2) A test of independence in a contingency table with five rows and four columns has the following degrees of freedom:
A. 12
B. 20
C. 9
D. 7

3) An inverse relationship between an independent variable x and a dependent variable y means that, as x increases, y decreases, and vice versa.
A. True
B. False

4) A pooled proportion estimate may be used to calculate the test statistic for a test of the equality of proportions when the
A. sample sizes are small.
B. samples are independently drawn from the populations.
C. null hypothesis states that the two population proportions are equal.
D. populations are normally distributed.

5) The appropriate measure of central location of ordinal data is the
A. mean.
B. median.
C. mode.
D. all of these.

19) Two independent samples of 20 each from male and female students of a large university have been selected at random. To test for difference in the grade point average between male and female students, the most likely ANOVA to fit this test situation is the A. two-factor ANOVA.
B. completely randomized design of the analysis of variance
C. randomized block design.
D. chi-square test .

6) The nonparametric counterpart of the parametric one-way analysis of variance F-test is the
A. Friedman test.
B. Kruskal-Wallis test.
C. Spearman’s rho.
D. Wilcoxon signed rank sum test.

7) Which of the following statements regarding multicollinearity is not true?
A. It does not affect the F-test of the analysis of variance.
B. It is also called collinearity and intercorrelation.
C. It exists in virtually all multiple regression models.
D. It is a condition that exists when independent variables are highly correlated with dependent variable.

8) If we simultaneously examine the effects of two factors on the dependent variable, along with the effects of interactions between different levels of those factors, we are performing a three-factor analysis of variance.
A. True
B. False

9) Which of the following statistics from the ANOVA table do not have an additive relationship?
A. Degrees of freedom
B. Sum of squares
C. Mean squares
D. It is not possible to tell.

10) Consider the following data set: 14, 14, 15, 16, 18, 19, 19, 20, 21, 22, 23, 25, 25, 25, 25, and 28. The rank assigned to the four observations of value 25 is
A. 12.5
B. 12
C. 13
D. 13.5

11) The Kruskal-Wallis test statistic may be approximated by a chi-squared distribution with c-1 degrees of freedom, where c is the number of populations, whenever the sample sizes are all greater than or equal to
A. 15
B. 30
C. 25
D. 5

12) When no point lies outside the control limits of a chart, we conclude that variation in the process is
A. due to special causes and there is enough evidence to infer that the process is under control.
B. due to common cause and there is enough evidence to infer that the process is out of control.
C. due to common cause and there is enough evidence to infer that the process is out of control.
D. due to special causes and there is not enough evidence to infer that the process is out of control.

13) The regression line y = 2 + 3x has been fitted to the data points (4,11), (2,7), and (1,5). The sum of squares for error will be 10.0
A. True
B. False

14) Which of the following is not required to perform a one-factor ANOVA?
A. The populations must be normally distributed.
B. The sample sizes must be equal.
C. The population variances must be equal.
D. The samples for each treatment must be selected randomly and independently.

15) If the Durbin-Watson statistic, DW, has values greater than 2, this indicates
A. a positive first–order autocorrelation.
B. a negative first–order autocorrelation.
C. no first–order autocorrelation at all.
D. None of the above

16) Of the values for a chi-squared test statistic listed below, which one is most likely to lead to rejecting the null hypothesis in a goodness-of-fit test?
A. 2.1
B. 45
C. 1.2
D. 0


17) If a group of independent variables are not significant individually but are significant as a group at a specified level of significance, this is most likely due to
A. multicollinearity.
B. the presence of binary variables.
C. the absence of binary variables.
D. autocorrelation

31) In regression analysis, if the coefficient of determination is 1.0, then the coefficient of correlation must be 1.0.
A. True
B. False

18) The purpose of designing a randomized block experiment is to reduce the between-treatments variation (SST) to more easily detect differences between the treatment means. A. True
B. False

19) From the coefficient of multiple determination, we cannot detect the strength of the relationship between the dependent variable y and any individual independent variable. A. True
B. False


20) When the only sources of variation in a production process are caused by chance, the process is said to be
A. out of control but in balance.
B. under control.
C. out of control.
D. out of balance but under control.




21) If each group has at least five observations, the distribution of the Kruskal-Wallis H is
A. t
B. F
C. x2
D. z

22) The distribution for Spearman’s rho is
A. t
B. z
C. x2.
D. F

23) What randomness exists in the linear regression model?
A. The randomness from the explanatory variables, the X's
B. The randomness from what is unexplained, the error
C. The randomness of the dependent variable, the Y's
D. None of these

24) The bivariate correlation coefficient always has the same sign as b1 in Y = b0 + b1X. A. True
B. False

25) Given that SSE = 84 and SSR = 358.12, the coefficient of correlation, also called the Pearson coefficient of correlation, must be 0.90.
A. True
B. False

26) In two-factor ANOVA, the MSE must always be positive, but MSA or MSB may be negative.
A. True
B. False



27) The time series component that reflects variability over short, repetitive time periods that last less than one year is called
A. cyclical variation.
B. irregular variation.
C. seasonal variation.
D. long–term trend.

28) A time series is
A. a set of measurements on a variable taken over some time period in chronological order.
B. a model that attempts to analyze the relationship between a dependent variable and one or more independent variables.
C. a model that attempts to forecast the future value of a variable.
D. a set of measurements on a variable collected at the same time or approximately the same period of time.

29) If we want to measure the seasonal variations on stock market performance by quarter, we would need
A. 3 indicator variables.
B. 2 indicator variables.
C. 1 indicator variables.
D. 4 indicator variables.


30) Variations in output that are caused by specific temporary events such as machine malfunction are
A. special causes.
B. common causes.
C. out-of-control causes.
D. All of the these


31) The time series component that reflects variability over short, repetitive time periods that last less than one year is called
A. cyclical variation.
B. irregular variation.
C. seasonal variation.
D. long–term trend.

32) If the Durbin-Watson statistic, DW, has values greater than 2, this indicates
A. a positive first–order autocorrelation.
B. a negative first–order autocorrelation.
C. no first–order autocorrelation at all.
D. None of the above

Exam : 4
1) A sufficiently large coverage error will result in which of the following?

A

B. Statistics about the actual population rather than the target population

B

C. Non-response bias

C

D. Inability to perform inferential statistics

D.

Probability sampling

 2) What is the difference between probability sampling and simple random sampling?
A.
.....
Probability sampling is a type of simple random sample.
B.
.....
In probability sampling each item has an identical chance of being chosen.
C.
.....
There is no difference.
D.
.....
Simple random sampling is a type of probability sampling.
3) A recent study of breast cancer revealed that 13% of the women in the sample used antibiotics more than 500 days in their lifetime. Further, 79% of these “heavy antibiotics users” developed breast cancer. According to the American Cancer Society, one in twelve women will develop breast cancer at some time in her life. Of the numbers mentioned, which are parameters?

A

79% and 500 days

B

13% and 79%

C

13% and one in twelve

D.

79% and one in twelve

4) Which of the following statements is false?

A

A. A summary measure calculated from some of the items of interest is a statistic.

B

B. A summary measure calculated from all items of interest is a parameter.

C.

The main goal of descriptive statistics is to estimate characteristics of populations.

D

D. Statistical inference is the process of making a prediction based on only a small piece of information.

5) Which of the following statements is not true?

A

A. Statistics is the science of collecting, organizing, analyzing, interpreting, and presenting data.

B

B. Scientific progress consists of continual refinement of theories through hypothesis testing.

C.

Estimating parameters is an important aspect of descriptive statistics.

D

D. A statistical test may be significant yet have no practical importance.

6) The collection and summarization of the socioeconomic and physical characteristics of the employees of a particular firm is an example of

A

a statistic.

B.

descriptive statistics.

C

a parameter.

D

inferential statistics.
7) The average score for a class of 30 students was 75. The 20 male students in the class averaged 70. The 10 female students in the class averaged

A.

85

B

75

C

85

D

90

8) A child was born into the Doe family each year for five consecutive years. What is the variance of the ages of the Doe children?

A

1.4 

B

4.6

C.

2.0

D

2.5

9) 
Textbook Price
Number of Textbooks
$25 to $35
2
35 to 45
16
45 to 55
5
55 to 65
7
65 to 75
20
Estimate the standard deviation of the price of a textbook.

A

B. 33.85

B.

14.03

C

C. 196.78

D

D. 729.00


13) Past history shows that 70% of college students prefer Pepsi. Groups of nine students are selected. Describe the histogram that would represent this distribution. The histogram would be:

A

B. right-skewed with ten columns.

B.

left-skewed with ten columns.

C

C. right-skewed with nine columns.

D

D. left-skewed with nine columns.

16) Which of the following statements is consistent with the Central Limit Theorem?

A

When we know s, the variation in the sample means will be equal to that of the population.

B

If a population has µ and s, a sample from that population will be normally distributed if the sample size is large enough.

C.

Means of samples of n=30 from an exponential distribution will be approximately normally distributed.

D

When µ and s are known, the population will be approximately normally distributed.

17) The standard error of the sample mean is equal to 5 when n=25. If the sample size increases by a factor of four, how will the standard error change?




A.
.....
It will quadruple




B.
.....
It will be cut to ¼ of 5




C.
.....
It will double




D.
.....
It will be cut in half

18) The use of the student’s t distribution requires which of the following assumptions?

A

A. The sample size is greater than 30

B

B. The sample is drawn from a positively skewed distribution

C

C. The population variance is known

D.

The population is normal
22) When no point lies outside the control limits of a chart, we conclude that variation in the process is

A

A. due to special causes and there is not enough evidence to infer that the process is out of control.

B

C. due to special causes and there is enough evidence to infer that the process is under control.

C

D. due to common cause and there is enough evidence to infer that the process is out of control.

D.

due to common cause and there is not enough evidence to infer that the process is out of control.

23) When the results of a process are either defective or acceptable, the charts used for SPC are called

A.

control charts for attributes.

B

B. control charts for variables.

C

C. control charts for in control process.

D

D. control charts for out of control process.


20) 
A study of 200 insomniacs paid for by the Serta Mattress Company found that the average insomniac counted 350 sheep before falling asleep, with a standard deviation of 120.  An insomniac is a person who has difficulty falling asleep.  Some useful numbers might be:
=NORMSINV(0.89)
1.2265
=NORMSINV(0.945)
1.5982
=TINV(0.89,199)
0.1385
=TINV(0.11,199)
1.6053
=TINV(0.055,199)
1.9302     

Calculate an 89% confidence interval for the true mean number of sheep counted by insomniacs.

A

C. 350±10.41

B

A. 350±16.38

C

D. 350±13.56

D.

350±13.62

21) What does it mean to have 95% confidence in an interval estimate?

A

A. In repeated sampling, the population parameter would fall in the given 95% of the time.

B.

In repeated sampling, 95% of the intervals would contain the population parameter.

C

B. In repeated sampling, 95% of the population observations fall within the given interval

D

D. In repeated sampling, 95% of the point estimates fall within the given interval.

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