correlation and regression

PREPARED BY: FAR (JULY 2021)

UNIVERSITI KUALA LUMPUR MALAYSIAN INSTITUTE OF MARINE ENGINEERING TECHNOLOGY LGB 23103 TEST 2

TEST 2: CORRELATION AND REGRESSION

ANSWER ALL QUESTIONS

1. The marketing manager of a large supermarket chain would like to use shelf space o

predict the sales of pet food. A random sample of 12 equal-sized stores is selected,

with the following results (Table 1).

STORE SHELF SPACE ( X ) (Feet) WEEKLY SALES (Y ) (RM)

1 5 160

2 5 220

3 5 140

4 10 190

5 10 240

6 10 260

7 15 230

8 15 270

9 15 280

10 20 260

11 20 290

12 20 310

Table 1

(a) Construct a scatter diagram.

(3 Marks)

(b) Determine the regression line, y  .

(8 Marks)

(c) Interpret the meaning of slope, b , in this problem.

(2 Marks)

(d) Predict the weekly sales of pet food for stores with 8 feet of shelf space for

pet food.

(2 Marks)

PREPARED BY: FAR (JULY 2021)

UNIVERSITI KUALA LUMPUR MALAYSIAN INSTITUTE OF MARINE ENGINEERING TECHNOLOGY LGB 23103 TEST 2

2. A car dealership owner wishes to determine if there is relationship between the

number of years of experience a salesperson has and the number of cars sold per

month. The data are given here (Table 2).

Year of

experience, x 3 9 2 5 1

No of car sold per

month, y 5 14 12 21 8

Table 2

(a) Construct a scatter diagram.

(3 Marks)

(b) Determine the value of Pearson Product Moment correlation coefficient, r .

(8 Marks)

(c) Testing the significant of r at 05.0= .

(7 Marks)

(d) Calculate the regression line.

(4 Marks)

(e) Plot the regression line in (a).

(2 Marks)

(f) Summarize the result in (d).

(1 Mark)

REGRESSION AND CORRELATION

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