6.2 Linear Regressions

A linear regression is the process of mathematically finding the line of best fit. Once you have a linear regression completed, you can interpolate and extrapolate accurately.

We're going to do all the calculations on the graphing calculators, but the process for determining the linear regression involves the use of Least-Squares fit in order to minimize the residuals.

In order to describe a line, we need a slope and a y-intercept in the form

and

Ex 1 The following table indicates rabbit and wolf population over the course of 8 years

Year	1994	1995	1996	1997	1998	1999	2000	2001
Rabbit	61	72	78	76	65	54	39	43
Wolf	26	33	42	49	37	30	24	19

(a) Determine the line of best fit and correlation coefficient for these data.

(b) Graph the data and predict the populations today.

Ex 2 The table shows the number of hours of instruction in driving versus the score on the driving test.

Hours	10	15	21	6	18	20	12
Score	78	85	96	75	84	45	82

(a) Graph the scatter plot and the line of best fit for this data.

(b) Comment on any data that seems unusual.

p. 180# 1, 2, 5, 6, 7