Algebra 2
Linear & Quadratic Regression
Name: _______________________
Block: ______ Date: ____________
Regression:
The process of finding an equation that best fits the data points in the scatter plot
What is this used for?
How do we find the best fit model?
1) Enter data: STAT 1: Edit
2) Turn on Stat Plot: 2nd y = to Plot1, then ENTER. Plot1 on should be darkened.
3) Determine if data is linear or quadratic: ZOOM #9:ZoomStat to look at graph.
4) STAT -> CALC 4:LinReg for a linear function (if the scatter plot looks like a line)
5:QuadReg for a quadratic function (if it looks like a part of parabola).
5) Useful tip: to enter the regression equation into y = click VARS , y-vars after you have
chosen your type of regression (or into field: store RegEQ) before hitting enter
Examples:
The heights and weights of some students are listed below. Find the equation of the best fit
model.
x
y
Height (in)
Weight (lbs)
Linear or Quadratic?
60
105
62
111
64
123
66
130
68
139
70
149
72
158
Best fit model: y = ________________________
Use this model to predict the weight of a student who is 55 inches tall.
Use this model to predict the height of a student who weighs 136 pounds.
2. The following table shows the number of participants y in the local youth football program
from 2000 to 2005. Assume that t is the number of years since 2000.
Year, t
Participants, y
0
24
1
28
2
33
3
41
4
54
5
74
a) Is the data best represented by a linear or quadratic model? Write the equation of the best
fit model.
b) Using the model to determine how many participants there were in 1998.
3.
x
y
Experience (months)
Typing Speed (wpm)
4
33
7
45
8
46
1
20
6
40
3
30
5
38
2
22
9
52
6
44
7
42
Find the equation of the best model for the relationship between experience and typing speed.
If I have 1 year of experience, based on the model what do you think my typing speed would
be?
If you want to hire an administrative assistant who can type at least 43 words per minute, do
you think you would hire someone with 6 and half months of experience?
10
55