Question

Bradford Electric Illuminating Company is studying the relationship between kilowatt-hours (thousands) used and the number of rooms in a private single-family residence. A random sample of 10 homes yielded the following.

Determine the value of Ŷ when X = 7

Number of Rooms

12

9

14

6

10

8

10

10

5

7

Kilowatt-Hours (thousands)

9

7

10

5

8

6

8

10

4

7

Answer 1

Number of Rooms =x , Kilowatt-Hours (thousands) =y

By using excel we can solve this question.

First, enter data into excel.

Least square Regression line is   

Here a is intercept and b is the slope.

We have to find values of a and b.

For finding value of 'a' use excel command =INTERCEPT(select y values , select x values)

We get a = 1.333

For finding value of b use excel command =SLOPE(select y values , select x values)

We get b = 0.667

So Least square Regression line is = 1.333 + ( 0.667) *x

when X = 7

= 1.333 + ( 0.667) *(7)