Use linear regression to find the equation of the line that best fits the data

Question

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. At what age is the game system​ worthless?

age (years) retail price

1 498

2 390

3 346

4 253

5 185

Answer 1

Alysia

If you have a TI-84, put the ages in list 1, the retail price in list 2, then do a linear regression (STAT CALC 4)

Gives a = -76.3, b = 563.3

So the model is retail price = -76.3 x age + 563.3

r = - 0.9938 indicating a nearly perfect negative correlation (so the model predicts very well)

Then you can use this model to find price when age = 7

And it is worthless when retail price = 0, so again use the model to find the age then

Mike