Question

The table below represents the closing cost of ABC for the last 5 days. What is the r -value of the linear regression that fits these data?

Day Value
1 20.71
2 19.69
3 19.61
4 19.64
5 19.26

Choices are as follows
A. -0.79631
B. 0.86493
C. 0.91237
D. -0.85650

Answer 1

Answer: -0.94719

Explanation:

Answer 2

The correct option is D.

Explanation:

The linear regression equation is in the form of

`y=bx+a`

Where,

`b=(n(\sum xy)-(\sum x)(\sum y))/(n(\sum x^2)-(\sum x)^2)`

`a=((\sum y)(\sum x^2)-(\sum x)(\sum xy))/(n(\sum x^2)-(\sum x)^2)`

The formula of r is

`r=(n(\sum xy)-(\sum x)(\sum y))/(√([n(\sum x^2)-(\sum x)^2][n(\sum y^2)-(\sum y)^2]))`

The values are

`\sum x=15,\sum y=98.91,\sum x^2=55,\sum y^2=1957.8295,\sum xy=293.78, n=5`

Using above formula, we get

`r=-0.85650`

Therefore option D is correct.