Use linear regression to find the equation of the line that best fits the data. Predict the average retail price of a game system that is 7 years old in the spring of 1997...

Question

...At what age is the game system worthless?

Age (years) Retail Price ($)

1 497

2 418

3 330

4 239

5 173

The regression line is

R=

​(Round the coefficients to the nearest​ hundredth; use A for the age and R for the retail​ price.)

I have no idea what I'm doing and me not having a graphing calculator doesn't help, any answers or tips help!!!

Answer 1

As Steven said, it might be best to do this on a spreadsheet in Excel or Google Sheets. The formula for the regression line is

R = b₀ + b₁*A

and we first find b₁ with the formula

Σ [ (A_i - average of A)(R_i - average of R) ] / Σ [ (A_i - average of A)²],

where i is the point number. Then, we can plug b₁ in the formula

b₀ = average of R - b₁*average of A

to solve for b₀.

The answer I got is R = 579.50 - 82.70*A. Please feel free to check it.

Answer 2

You may use Excel or Google SpreadSheet to plot the data in a chart. Then add a trend line to your data and show the equation and R2.

The equation is R = -82.7 A + 580.

The math to calculate the coefficients a and b for equation y = ax + b is below: