devry math221n week 3 quiz latest 2016 july

devry math221n week 3 quiz latest 2016 july

1. The equation used to predict college GPA (range 0-4.0) is

y=0.19+0.51x1+0.002x2,

where

x1

is high school GPA (range 0-4.0) and

x2

is college board score (range 200-800). Use the multiple regression equation to predict college GPA for a high school GPA of

3.1

and a college board score of

500.

The predicted college GPA for a high school GPA of

3.1

and a college board score of

500

is

(Round to the nearest tenth as needed.)

2.

The numbers of regular season wins for 10 football teams in a given season are given below. Determine the range, mean, variance, and standard deviation of the population data set.

2

8,

15,

5,

11

10,

15,

10,

3,

9

The range is

(Simplify your answer.)

The population mean is

(Simplify your answer. Round to the nearest tenth as needed.)

The population variance is

(Simplify your answer. Round to the nearest hundredth as needed.)

The population standard deviation is

.

(Simplify your answer. Round to the nearest tenth as needed.)

3.

Match this description with a description below.

The y dash value for a point on the regression line corresponding to xi

Choose the correct answer below.

A.

yi

.

B.

m

C.

b

D.

yi

4.

Determine whether the statement is true or false. If it is false, rewrite it as a true statement.

More types of calculations can be performed with data at the nominal level than with data at the interval level.

Choose the correct answer below.

A.

True.

B.

False. More types of calculations can be performed with data at the interval level than with data at the nominal level.

C.

False. The same types of calculations can be performed with data at the nominal level and with data at the interval level.

5.

Heights of men on a baseball team have a bell-shaped distribution with a mean of

169 cm

and a standard deviation of

6 cm.

Using the empirical rule, what is the approximate percentage of the men between the following values?

a.

163

cm and

175

cm

b.

151

cm and

187

cm

a.

of the men are between

163

cm and

175

cm.

(Round to one decimal place as needed.)

b.

of the men are between

151

cm and

187

cm.

(Round to one decimal place as needed.)

6.

Identify the sampling techniques used, and discuss potential sources of bias (if any). Explain. Assume the population of interest is the student body at a university.

Questioning students as they leave

an academic buildingan

a researcher asks

362

students about their

eating

habits.

What type of sampling is used?

A.

Stratified sampling is used, because students are divided into groups, and students are chosen at random from these groups.

B.

Cluster sampling is used, because students are divided into groups, groups are chosen at random, and every student in one of those groups is sampled.

C.

Convenience sampling is used, because students are chosen due to convenience of location.

D.

Simple random sampling is used, because students are chosen at random.

E.

Systematic sampling is used, because students are selected from a list, with a fixed interval between students on the list.

What potential sources of bias are present, if any? Select all that apply.

A.

The sample only consists of members of the population that are easy to get. These members may not be representative of the population.

B.

University students may not be representative of all people in their age group.

C.

Because of the personal nature of the question, students may not answer honestly.

D.

There are no potential sources of bias.

7.

What is an inherent zero? Describe three examples of data sets that have inherent zeros and three that do not.

Choose the correct answer below.

A.

An inherent zero is a value that the variable can take.

B.

An inherent zero is a zero that implies none.

C.

An inherent zero is a zero that occurs in the data set naturally.

Select three examples of data sets that have inherent zeros below.

A.

Average IQ score of a high school class

Your answer is not correct.

B.

Maximum wind speed during a hurricane

This is the correct answer.

C.

Average monthly percipitation in inches

D.

Average age of college students in years

This is the correct answer.

E.

A student's level of happiness measured from 0 to 10

Your answer is not correct.

F.

Temperature in degrees Fahrenheit

Select three examples of data sets that do not have inherent zeros below.

A.

Average monthly percipitation in inches

B.

Maximum wind speed during a hurricane

Your answer is not correct.

C.

A student's level of happiness measured from 0 to 10

D.

Average age of college students in years

.

E.

Temperature in degrees Fahrenheit

.

F.

Average IQ score of a high school class

8.

Find the equation of the regression line for the given data. Then construct a scatter plot of the data and draw the regression line. (The pair of variables has a significant correlation.) Then use the regression equation to predict the value of y for each of the given x-values, if meaningful. The table shows the shoe size and heights (in) for 6 men.

font size decreased by 1 font size increased by 1 Shoe size comma xShoe size, x 8.5 9.0 9.5 12.0 13.0 13.5 (a)

xequals=size

10.0 (b)

xequals=size11.5

Height, y

65.0 67.0 70.0 69.0 71.0 73.0 (c)

xequals=size

16.5 (d)

xequals=size

10.5

Find the regression equation.

ModifyingAbove y with caret<="" path="">yequals (Round to three decimal places as needed.)

Construct a scatter plot of the data and draw the regression line. Plot shoe size on the horizontal axis and height on the vertical axis. Choose the correct graph below.

A.

font size decreased by 3 00

font size decreased by 3 6565

font size decreased by 3 7575

font size decreased by 3 88

font size decreased by 3 1414

x y graph

B.

font size decreased by 3 00

font size decreased by 3 6565

font size decreased by 3 7575

font size decreased by 3 88

font size decreased by 3 1414

x y graph

C.

font size decreased by 3 00

font size decreased by 3 6565

font size decreased by 3 7575

font size decreased by 3 88

font size decreased by 3 1414

x y graph

D.

font size decreased by 3 00

font size decreased by 3 6565

font size decreased by 3 7575

font size decreased by 3 88

font size decreased by 3 1414

x y graph

(a) Predict the value of y for

xequals=10.0

Choose the correct answer below.

A.

69..8

B.

68. 1

.

C.

68..7

D.

not meaningful

(b) Predict the value of y for

xequals=11.5.

Choose the correct answer below.

A.

69..8

B.

68..7

C.

75. 4

D.

not meaningful

(c) Predict the value of y for

xequals=16.5.

Choose the correct answer below.

A.

68. 1

B.

75. 4

C.

69..8

D.

not meaningful

(d) Predict the value of y for

xequals=10.5.

Choose the correct answer below.

A.

75.4

B.

68.7

C.

68.1

D.

not meaningful

Question is complete.

9.

Determine whether the data set is a population or a sample. Explain your reasoning.

The number of garages for each house on a street.

Choose the correct answer below.

A.

Sample, because it is a collection of

the number of garages for all housesthe number of garages for all houses

on the street commaon the street,

but there are other houses on different streets.

B.

Population, because it is a subset of all houses in the town.

C.

Population, because it is a collection of

the number of garages for all houses

on the street.on the street.

.

D.

Sample, because it is a collection of

number of garages for some houses

on the street.on the street.

10.

Suppose the scatter plot shows the results of a survey of

26

randomly selected males ages

24

to

35

Using age as the explanatory variable, choose the appropriate description for the graph. Explain your reasoning.

(a) Age and body temperature

(b) Age and balance on student loans

(c) Age and income

(d) Age and height

24262830323436020406080100AgeIn thousands of units

x y graph

The response variable is

because you would expect this variable and age to have

and

variation for adult males.

11.

Use the value of the linear correlation coefficient to calculate the coefficient of determination. What does this tell you about the explained variation of the data about the regression line? About the unexplainedvariation?

r=-0.407

Calculate the coefficient of determination.

0.166

(Round to three decimal places as needed.)

What does this tell you about the explained variation of the data about the regression line?

16.6%

of the variation can be explained by the regression line.

(Round to one decimal place as needed.)

About the unexplained variation?

83.4%

of the variation is unexplained and is due to other factors or to sampling error.

(Round to one decimal place as needed

12.

Find the equation of the regression line for the given data. Then construct a scatter plot of the data and draw the regression line. (The pair of variables have a significant correlation.) Then use the regression equation to predict the value of y for each of the given x-values, if meaningful. The number of hours 6 students spent for a test and their scores on that test are shown below.

font size decreased by 1 font size increased by 1 Hours spent studying comma xHours spent studying, x 1 2 33 44 55 66 (a)

x=33

hours (b)

x=3.5

hours

Test score, y

41 47 53 45 61 73 (c)

x=15

hours (d)

xequals=1.51.5

hours

Find the regression equation.

y^= 5.543x+( 33.933)

(Round to three decimal places as needed.)

Choose the correct graph below.

A.

08080Hours studyingTest score

x y graph

B.

08080Hours studyingTest score

x y graph

C.

08080Hours studyingTest score

x y graph

D.

08080Hours studyingTest score

x y graph

(a) Predict the value of y for

x=33.

Choose the correct answer below.

A.

50.6

B.

53.3

C.

42.2

D.

not meaningful

(b) Predict the value of y for

x=3.5.

Choose the correct answer below.

A.

53..3

B.

42.2

C.

117.1

D.

not meaningful

(c) Predict the value of y for

x15.

Choose the correct answer below.

A.

50.6

B.

53.3

C.

117.1

D.

not meaningful

(d) Predict the value of y for

x=1.5.

Choose the correct answer below.

A.

42.2

.

B.

50.6

C.

17.1

D.

not meaningful

13.

An auction company sold 15 handheld computers last month. The final prices (in dollars) at which the items sold are as follows.

254

249,

237,

205,

249,

229,

229,

232,

244,

229,

229

249,

213

213

249

a. Construct a stem-and-leaf plot. b. Summarize what this plot tells you about the data.

a.

Determine the leaves in the stem-and-leaf plot shown at the right.

(Use ascending order.)

Stems Leaves

20

21

22

23

24

25

b. Which of the following best summarizes what the stem-and-leaf plot tells you about the data?

A.

The plot does not show all the data. It only shows the prices that fall between

$ 200

and $260 inclusive.

B.

The plot gives an overview of all the data. It clearly shows that the prices fall between $200 and $260 inclusive.

C.

The plot gives an overview of all the data. It clearly shows that the prices fall between

$205

and

$254

inclusive.

D.

The plot does not show all the data. It only shows the prices that fall between

$ 205

and

$254

inclusive.

14.

Determine whether the given value is a statistic or a parameter.

A sample of students is selected and it is found that 55 % own a computer.

Choose the correct statement below.

Parameter

because the value is a numerical measurement describing a characteristic of a

populationpopulation.

Statistic

because the value is a numerical measurement describing a characteristic of a

population

Parameter

because the value is a numerical measurement describing a characteristic of a

samplesample.

Statistic

because the value is a numerical measurement describing a characteristic of a

sample.

15.

Match the plot with a possible description of the sample. 10

11

12

13

1 1 3 4 4 6 7 8 8

1 2 5 5 5

4

01 7 7

Key 10|1=101

Choose the correct answer below.

A.

Time left parenthesis in minutes right parenthesis it takes a sample of employees to drive to work

B.

Fastest serve left parenthesis in miles per hour right parenthesis of a sample of top tennis players

C.

Ages left parenthesis in years right parenthesis of a sample of residents of a retirement home

D.

Top speeds left parenthesis in miles per hour right parenthesis of a sample of sports cars

16.

Match the frequency distribution of

190

rolls of a dodecagon (a 12-sided die) with one of the histograms shown below.

369120510152025

x y graph 3691205101520

x y graph 369120510152025

x y graph 369120510152025

x y graph

Which histogram shows a distribution that would likely result from

190

rolls of a dodecagon?

A.

3691205101520

x y graph

B.

369120510152025

x y graph

C.

369120510152025

x y graph

D.

369120510152025