BUA 887 Midterm 2 | Course Paper

Unlock access to all the studying documents.

View Full Document

True or False: In testing a hypothesis, you should always raise the question concerning

the purpose of the study, survey or experiment.

True or False: If the values of the seventh and eighth class in a cumulative percentage

distribution are the same, we know that there are no observations in the eighth class.

True or False: TABLE 18-5

A manufacturer of computer disks took samples of 240 disks on 15 consecutive days.

The number of disks with bad sectors was determined for each of these samples. The

results are in the table that follows.

Referring to Table 18-5, the process seems to be in control.

TABLE 12-2

The dean of a college is interested in the proportion of graduates from his college who

have a job offer on graduation day. He is particularly interested in seeing if there is a

difference in this proportion for accounting and economics majors. In a random sample

of 100 of each type of major at graduation, he found that 65 accounting majors and 52

economics majors had job offers. If the accounting majors are designated as “Group 1”

and the economics majors are designated as “Group 2,” perform the appropriate

hypothesis test using a level of significance of 0.05.

True or False: Referring to Table 12-2, the same decision would be made with this test

if the level of significance had been 0.10 rather than 0.05.

True or False: A sample is used to obtain a 95% confidence interval for the mean of a

population. The confidence interval goes from 15 to 19. If the same sample had been

used to test the null hypothesis that the mean of the population is equal to 20 versus the

alternative hypothesis that the mean of the population differs from 20, the null

hypothesis could be rejected at a level of significance of 0.10.

True or False: The F test in a completely randomized model is just an expansion of the t

test for independent samples.

True or False: TABLE 17-9

What are the factors that determine the acceleration time (in sec.) from 0 to 60 miles per

hour of a car? Data on the following variables for 171 different vehicle models were

collected:

Accel Time: Acceleration time in sec.

Cargo Vol: Cargo volume in cu. ft.

HP: Horsepower

MPG: Miles per gallon

SUV: 1 if the vehicle model is an SUV with Coupe as the base when SUV and Sedan

are both 0

Sedan: 1 if the vehicle model is a sedan with Coupe as the base when SUV and Sedan

are both 0

The regression results using acceleration time as the dependent variable and the

remaining variables as the independent variables are presented below.

The various residual plots are as shown below.

The coefficient of partial determination ( ) of each of the 5

predictors are, respectively, 0.0380, 0.4376, 0.0248, 0.0188, and 0.0312.

The coefficient of multiple determination for the regression model using each of the 5

variables Xj as the dependent variable and all other X variables as independent variables

( ) are, respectively, 0.7461, 0.5676, 0.6764, 0.8582, 0.6632.

Referring to Table 17-9, the 0 to 60 miles per hour acceleration time of an SUV is

predicted to be 0.1252 seconds higher than that of a sedan.

TABLE 11-11

A student team in a business statistics course designed an experiment to investigate

whether the brand of bubblegum used affected the size of bubbles they could blow. To

reduce the person-to-person variability, the students decided to use a randomized block

design using themselves as blocks.

Four brands of bubblegum were tested. A student chewed two pieces of a brand of gum

and then blew a bubble, attempting to make it as big as possible. Another student

measured the diameter of the bubble at its biggest point. The following table gives the

diameters of the bubbles (in inches) for the 16 observations.

True or False: Referring to Table 11-11, the randomized block F test is valid only if the

population of diameters has the same variance for the 4 brands.

True or False: An investment consultant is recommending a certain class of mutual

funds to the clienteles based on its exceptionally high probability of gain. It is an ethical

practice to explain to the clienteles what the meaning of probability is.

True or False: Referring to Table 14-16, the 0 to 60 miles per hour

acceleration time of a sedan is predicted to be 0.0005 seconds lower

than that of a non-sedan with the same engine size.

TABLE 13-12

The manager of the purchasing department of a large saving and loan organization

would like to develop a model to predict the amount of time (measured in hours) it

takes to record a loan application. Data are collected from a sample of 30 days, and the

number of applications recorded and completion time in hours is recorded. Below is the

regression output:

True or False: Referring to Table 13-12, the model appears to be adequate based on the

residual analyses.

TABLE 11-5

A hotel chain has identically small sized resorts in 5 locations in different small islands.

The data that follow resulted from analyzing the hotel occupancies on randomly

selected days in the 5 locations.

Analysis of Variance

* or p < 0.005, tabular value

True or False: Referring to Table 11-5, if a level of significance of 0.05 is chosen, the

decision made indicates that all 5 locations have different mean occupancy rates.

True or False: A polygon can be constructed from a bar chart.

True or False: The purpose of a control chart is to eliminate common cause variation.

True or False: A test for the difference between two proportions can be performed using

the chi-square distribution.

TABLE 5-3

The following table contains the probability distribution for X = the number of

retransmissions necessary to successfully transmit a 1024K data package through a

double satellite media.

Referring to Table 5-3, the standard deviation of the number of retransmissions is

________.

TABLE 17-10

Given below are results from the regression analysis where the dependent variable is

the number of weeks a worker is unemployed due to a layoff (Unemploy) and the

independent variables are the age of the worker (Age), the number of years of education

received (Edu), the number of years at the previous job (Job Yr), a dummy variable for

marital status (Married: 1 = married, 0 = otherwise), a dummy variable for head of

household (Head: 1 = yes, 0 = no) and a dummy variable for management position

(Manager: 1 = yes, 0 = no). We shall call this Model 1. The coefficient of partial

determination ( ) of each of the 6 predictors are, respectively,

0.2807, 0.0386, 0.0317, 0.0141, 0.0958, and 0.1201.

Model 2 is the regression analysis where the dependent variable is Unemploy and the

independent variables are Age and Manager. The results of the regression analysis are

given below:

Referring to Table 17-10, Model 1, which of the following is the correct alternative

hypothesis to determine whether there is a significant relationship between the number

of weeks a worker is unemployed due to a layoff and the entire set of explanatory

variables?

A) H1 : All Î²j â‰ 0 for j = 0, 1, 2, 3, 4, 5, 6

B) H1 : All Î²j â‰ 0 for j = 1, 2, 3, 4, 5, 6

C) H1 : At least one of Î²j â‰ 0 for j = 0, 1, 2, 3, 4, 5, 6

D) H1 : At least one of Î²j â‰ 0 for j = 1, 2, 3, 4, 5, 6

TABLE 4-1

Mothers Against Drunk Driving is a very visible group whose main focus is to educate

the public about the harm caused by drunk drivers. A study was recently done that

emphasized the problem we all face with drinking and driving. Four hundred accidents

that occurred on a Saturday night were analyzed. Two items noted were the number of

vehicles involved and whether alcohol played a role in the accident. The numbers are

shown below:

Referring to Table 4-1, given alcohol was involved, what proportion of accidents

involved a single vehicle?

A) 50/75 or 66.67%

B) 50/170 or 29.41%

C) 120/170 or 70.59%

D) 120/400 or 30%

TABLE 17-1

A real estate builder wishes to determine how house size (House) is influenced by

family income (Income), family size (Size), and education of the head of household

(School). House size is measured in hundreds of square feet, income is measured in

thousands of dollars, and education is in years. The builder randomly selected 50

families and ran the multiple regression. Microsoft Excel output is provided below:

Referring to Table 17-1, what is the value of the calculated F test statistic that is

missing from the output for testing whether the whole regression model is significant?

A) 0.0001

B) 0.0299

C) 0.726

D) 45.5340

The Y-intercept (b0) represents the

A) estimated average Y when X = 0.

B) change in estimated average Y per unit change in X.

C) predicted value of Y.

D) variation around the sample regression line.

The principal focus of the control chart is the attempt to separate special or assignable

causes of variation from common causes of variation. Which causes of variation can be

reduced only by changing the system?

A) Special or assignable causes

B) Common causes

C) Total causes

D) None of the above

TABLE 17-1

A real estate builder wishes to determine how house size (House) is influenced by

family income (Income), family size (Size), and education of the head of household

(School). House size is measured in hundreds of square feet, income is measured in

thousands of dollars, and education is in years. The builder randomly selected 50

families and ran the multiple regression. Microsoft Excel output is provided below:

Referring to Table 17-1, suppose the builder wants to test whether the coefficient on

Income is significantly different from 0. What is the value of the relevant t-statistic?

A) 5.286

B) 5.195

C) 3.945

D) -1.509

TABLE 15-2

In Hawaii, condemnation proceedings are under way to enable private citizens to own

the property that their homes are built on. Until recently, only estates were permitted to

own land, and homeowners leased the land from the estate. In order to comply with the

new law, a large Hawaiian estate wants to use regression analysis to estimate the fair

market value of the land. The following model was fit to data collected for n = 20

properties, 10 of which are located near a cove.

where Y = Sale price of property in thousands of dollars

X1 = Size of property in thousands of square feet

X2 = 1 if property located near cove, 0 if not

Using the data collected for the 20 properties, the following partial output obtained

from Microsoft Excel is shown:

Referring to Table 15-2, is the overall model statistically adequate at a 0.05 level of

significance for predicting sale price (Y)?

A) No, since some of the t tests for the individual variables are not significant.

B) No, since the standard deviation of the model is fairly large.

C) Yes, since none of the -estimates are equal to 0.

D) Yes, since the p-value for the test is smaller than 0.05.

TABLE 2-6

A sample of 200 students at a Big-Ten university was taken after the midterm to ask

them whether they went bar hopping the weekend before the midterm or spent the

weekend studying, and whether they did well or poorly on the midterm. The following

table contains the result.

Referring to Table 2-6, if the sample is a good representation of the population, we can

expect ________ percent of those who did poorly on the midterm to have spent the

weekend studying.

A) 10

B) 22

C) 45

D) 50

TABLE 17-9

What are the factors that determine the acceleration time (in sec.) from 0 to 60 miles per

hour of a car? Data on the following variables for 171 different vehicle models were

collected:

Accel Time: Acceleration time in sec.

Cargo Vol: Cargo volume in cu. ft.

HP: Horsepower

MPG: Miles per gallon

SUV: 1 if the vehicle model is an SUV with Coupe as the base when SUV and Sedan

are both 0

Sedan: 1 if the vehicle model is a sedan with Coupe as the base when SUV and Sedan

are both 0

The regression results using acceleration time as the dependent variable and the

remaining variables as the independent variables are presented below.

The various residual plots are as shown below.

The coefficient of partial determination ( ) of each of the 5

predictors are, respectively, 0.0380, 0.4376, 0.0248, 0.0188, and 0.0312.

The coefficient of multiple determination for the regression model using each of the 5

variables Xj as the dependent variable and all other X variables as independent variables

( ) are, respectively, 0.7461, 0.5676, 0.6764, 0.8582, 0.6632.

Referring to Table 17-9, what is the correct interpretation for the estimated coefficient

for Cargo Vol?

A) As the 0 to 60 miles per hour acceleration time increases by one second, the mean

cargo volume will increase by an estimated 0.0259 cubic foot without taking into

consideration all the other independent variables included in the model.

B) As the cargo volume increases by one cubic foot, the mean 0 to 60 miles per hour

acceleration time will increase by an estimated 0.0259 seconds without taking into

consideration all the other independent variables included in the model.

C) As the 0 to 60 miles per hour acceleration time increases by one second, the mean

cargo volume will increase by an estimated 0.0259 cubic foot taking into consideration

all the other independent variables included in the model.

D) As the cargo volume increases by one cubic foot, the mean 0 to 60 miles per hour

acceleration time will increase by an estimated 0.0259 seconds taking into

consideration all the other independent variables included in the model.

The estimation of the population average family expenditure on food based on the

sample average expenditure of 1,000 families is an example of

A) inferential statistics.

B) descriptive statistics.

C) DCOVA framework.

D) operational definition.

TABLE 17-12

The marketing manager for a nationally franchised lawn service company would like to

study the characteristics that differentiate home owners who do and do not have a lawn

service. A random sample of 30 home owners located in a suburban area near a large

city was selected; 15 did not have a lawn service (code 0) and 15 had a lawn service

(code 1). Additional information available concerning these 30 home owners includes

family income (Income, in thousands of dollars), lawn size (Lawn Size, in thousands of

square feet), attitude toward outdoor recreational activities (Attitude 0 = unfavorable, 1

= favorable), number of teenagers in the household (Teenager), and age of the head of

the household (Age).

The Minitab output is given below:

Referring to Table 17-12, which of the following is the correct interpretation for the

Income slope coefficient?

A) Holding constant the effect of the other variables, the estimated number of lawn

services purchased increases by 0.2868 for each increase of one thousand dollars in

family income.

B) Holding constant the effect of the other variables, the estimated average number of

lawn services purchased increases by 0.2868 for each increase of one thousand dollars

in family income.

C) Holding constant the effect of the other variables, the estimated probability of

purchasing a lawn service increases by 0.2868 for each increase of one thousand dollars

in family income.

D) Holding constant the effect of the other variables, the estimated natural logarithm of

the odds ratio of purchasing a lawn service increases by 0.2868 for each increase of one

thousand dollars in family income.

The Kruskal-Wallis test is an extension of which of the following for two independent

samples?

A) Pooled-variance t test

B) Paired-sample t test

C) Wilcoxon rank sum test

D) McNemar test

TABLE 19-2

The following payoff matrix is given in dollars.

Suppose the probability of Event 1 is 0.5 and Event 2 is 0.5.

Referring to Table 19-2, the EMV for Action A is

A) $300.

B) $550.

C) $600.

D) $700.

Which of the following is used to find a “best” model?

A) Odds ratio

B) Mallow’s Cp

C) Standard error of the estimate

D) SST

TABLE 11-8

A physician and president of a Tampa Health Maintenance Organization (HMO) are

attempting to show the benefits of managed health care to an insurance company. The

physician believes that certain types of doctors are more cost-effective than others. One

theory is that Primary Specialty is an important factor in measuring the

cost-effectiveness of physicians. To investigate this, the president obtained independent

random samples of 20 HMO physicians from each of 4 primary specialties – General

Practice (GP), Internal Medicine (IM), Pediatrics (PED), and Family Physicians (FP) –

and recorded the total charges per member per month for each. A second factor which

the president believes influences total charges per member per month is whether the

doctor is a foreign or USA medical school graduate. The president theorizes that foreign

graduates will have higher mean charges than USA graduates. To investigate this, the

president also collected data on 20 foreign medical school graduates in each of the 4

primary specialty types described above. So information on charges for 40 doctors (20

foreign and 20 USA medical school graduates) was obtained for each of the 4

specialties. The results for the ANOVA are summarized in the following table.

Referring to Table 11-8, what was the total number of doctors included in the study?

A) 20

B) 40

C) 159

D) 160

Blossom’s Flowers purchases roses for sale for Valentine’s Day. The roses are purchased

for $10 a dozen and are sold for $20 a dozen. Any roses not sold on Valentine’s Day can

be sold for $5 per dozen. The owner will purchase 1 of 3 amounts of roses for

Valentine’s Day: 100, 200, or 400 dozen roses. The opportunity loss for buying 200

dozen roses and selling 100 dozen roses at the full price is

A) $1,000.

B) $500.

C) -$500.

D) -$2,000.

Which of the following is not a reason for selecting a sample?

A) A sample is less time consuming than a census.

B) A sample is less costly to administer than a census.

C) A sample is usually not a good representation of the target population.

D) A sample is less cumbersome and more practical to administer.

TABLE 17-1

A real estate builder wishes to determine how house size (House) is influenced by

family income (Income), family size (Size), and education of the head of household

(School). House size is measured in hundreds of square feet, income is measured in

thousands of dollars, and education is in years. The builder randomly selected 50

families and ran the multiple regression. Microsoft Excel output is provided below:

Referring to Table 17-1, one individual in the sample had an annual income of

$100,000, a family size of 10, and an education of 16 years. This individual owned a

home with an area of 7,000 square feet (House = 70.00). What is the residual (in

hundreds of square feet) for this data point?

A) 7.40

B) 2.52

C) -2.52

D) -5.40

Referring to Table 14-7, the net regression coefficient of X2 is ________.

TABLE 14-7

The department head of the accounting department wanted to see if

she could predict the GPA of students using the number of course

units (credits) and total SAT scores of each. She takes a sample of

students and generates the following Microsoft Excel output:

TABLE 10-6

To investigate the efficacy of a diet, a random sample of 16 male patients is selected

from a population of adult males using the diet. The weight of each individual in the

sample is taken at the start of the diet and at a medical follow-up 4 weeks later.

Assuming that the population of differences in weight before versus after the diet

follow a normal distribution, the t-test for related samples can be used to determine if

there was a significant decrease in the mean weight during this period. Suppose the

mean decrease in weights over all 16 subjects in the study is 3.0 pounds with the

standard deviation of differences computed as 6.0 pounds.

Referring to Table 10-6, a one-tail test of the null hypothesis of no difference would

________ (be rejected/not be rejected) at the = 0.05 level of significance.

TABLE 16-15

Given below are the average prices for three types of energy products for five

consecutive years.

Referring to Table 16-15, what is the unweighted aggregate price index for the group of

three energy items in year 3 using year 1 as the base year?

You were told that the mean score on a statistics exam is 75 with the scores normally

distributed. In addition, you know the probability of a score between 55 and 60 is

4.41% and that the probability of a score greater than 90 is 6.68%. What is the

probability of a score between 55 and 90?

If a researcher does not reject a true null hypothesis, she has made a(n) ________

decision.

TABLE 3-3

The ordered array below represents the number of vitamin supplements sold by a health

food store in a sample of 16 days.

19, 19, 20, 20, 22, 23, 25, 26, 27, 30, 33, 34, 35, 36, 38, 41

Note: For this sample, the sum of the values is 448, and the sum of the squared

differences between each value and the mean is 812.

Referring to Table 3-3, construct a boxplot for the data in this sample.

TABLE 9-11

An appliance manufacturer claims to have developed a compact microwave oven that

consumes a population mean of no more than 250 W. From previous studies, it is

believed that power consumption for microwave ovens is normally distributed with a

population standard deviation of 15 W. If there is evidence that the population mean

consumption is greater than 250 W, the manufacturer will be unable to make the claim.

Referring to Table 9-11, if you select a sample of 20 compact microwave ovens and are

willing to have a level of significance of 0.05, the power of the test is ________ if the

mean power consumption of all such microwave ovens is in fact 248 W.

TABLE 18-5

A manufacturer of computer disks took samples of 240 disks on 15 consecutive days.

The number of disks with bad sectors was determined for each of these samples. The

results are in the table that follows.

Referring to Table 18-5, the best estimate of the mean proportion of disks with bad

sectors is ________.

TABLE 3-4

The ordered array below represents the number of cargo manifests approved by customs

inspectors of the Port of New York in a sample of 35 days:

16, 17, 18, 18, 19, 20, 20, 21, 21, 21, 22, 22, 22, 22, 23, 23, 23, 23, 24, 24, 24, 25, 25,

26, 26, 26, 27, 28, 28, 29, 29, 31, 31, 32, 32

Note: For this sample, the sum of the values is 838, and the sum of the squared

differences between each value and the mean is 619.89.

Referring to Table 3-4, the first quartile of the customs data is ________.