Quiz # 3 Date:_________ Section: _______ Name: ___________________________________________

An agent for a residential real estate company would like to be able to use regression technique to predict the monthly rent cost for

apartments based on the size of the apartments as defined by square footage. A sample of 12 apartments in a particular identical

neighborhood was selected, and the data are as: Use the data and plot the data as a scattered diagram.

X =Size Y= Rent

1235 $1560

1090 1345

950 1100

1325 1700

817 950

1845 1700

1136 1650

850 900

1100 1300

1825 1950

1450 1550

1230 1350

1) Comment on the pattern of the points? 1) _________

A. Perfect positive B. Positive C. Strong positive D. Weak positive

2) Compute the r ï€½ correlation coefficient 2) ________

A) 0.786 B) 0.867 C) 0.768 D) 0.895

3) Compute the slope and y-intercept 3) _________ A) 0 .76,283 B) 383.7,0 .84 C) 0 .84, 383.7 D) 283,0 .76

4) Write the equation of regression line 4) __________

A) y x ï€½ ï€« 0.76 283 B) y x ï€½ ï€« 383.7 0.84 C) y x ï€½ 0.84 383.7 ï€« D) y x ï€½ 283 0.76 ï€«

5) If the rent is $1000, use the regression equation answer in part 4 to estimate square footage. 5) _________

A) 943.42 B) 733.69 C) 934.42 D) 769.33

6) If the square footage is 1050, use the regression equation answer in part 4 to estimate rent. 6) ________

A) 1256.71 B) 1081.2 C) 1265.7 D) 1018.2

7) Compute average rent, 7) ________

A) $1412.25 B) $1421.25 C) $1141.25 D) $1214.25

8) Compute standard deviation for square footage 8) _________

A) 344.08 B) 324.7 C) 343.80 D) 334.08

9) Which of these statements about the correlation coefficient is false? 9) ________

A. r shows the strength and direction of the relationship between x, y variables when their relationship is linear

B. r varies between ï€1 and ï€«1.

C. r is strongest when it is close to ï€«1 and weakest or close to none when is close to 0.

D. For large data set the value of the r can be greater than ï€«1 or less thanï€1.

1

R

E

N

T

Size

1900

1700

1500

1300

1100

900

900 1100 1300 1500 1700 1900

800 1000 1200 1400 1600 1800 2000

1Å–) Researchers studying growth patterns of children collect data on the heights of fathers and sons.

The correlation between the fathersÊ¹ heights and the heights of their 16 year-old sons is most likely

to be...

A) near -1.0

B) exactly +1.0

C) somewhat greater than 1.0

D) near 0

E) near +0.7

11) The correlation between a familyÊ¹s weekly income and the amount they spend on restaurant meals

is found to be r = 0.30. Which must be true?

I. Families tend to spend about 30% of their incomes in restaurants.

II. In general, the higher the income, the more the family spends in restaurants.

III. The line of best fit passes through 30% of the (income, restaurant$) data points.

A) III only

B) I only

C) I, II, and III

D) II and III only

E) II only

12) It takes a while for new factory workers to master a complex assembly process. During the first

month new employees work, the company tracks the number of days they have been on the job

and the length of time it takes them to complete an assembly. The correlation is most likely to be

A) exactly -1.0

B) exactly +1.0

C) near 0

D) near +0.6

E) near -0.6

Provide an appropriate response.

13) The variable is the variable whose value can be explained by the

variable.

A) response; predictor B) predictor Response

C) response; lurking D) lurking; response

14) An instructor wishes to determine if there is a relationship between the number of absences from

his class and a studentÊ¹s final grade in the course. What is the predictor variable?

A) Final Grade

B) StudentÊ¹s performance on the final examination

C) The instructorÊ¹s point scale for attendance

D) Absences

15) Find the equation of the regression line for the given data. Round values to the nearest thousandth.

-5

-3

x

11

y

A) y^

= 0.206x - 2.097 B) y^

C) y^

= -2.097x + 0.206 D) y^

4

1

-6

8

-3

-1

-2

0

-2

1

5

2

3

-4

-5

6

7

= 2.097x - 0.206

= -0.206x + 2.097

Subject | Mathematics |

Due By (Pacific Time) | 02/10/2014 06:00 am |

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