**Scatter Graphs and Line of Best Fit**

Warm-Up

Write

increase

or

decrease

to complete the sentence regarding the expectations for the situation

Scatter graphs are used to show whether there is a relationship between two sets of data. The relationship between the data can be described as either:

Examples

Line of Best Fit

Line of best fit

can be drawn to data that shows a correlation. The stronger the correlation between the data, the easier it is to draw the line. The line can be drawn

by eye

and should have

roughly

the

same number

of data points on either side.

Objectives

The students will:

determine whether the data has positive, negative, or no correlation

use graphing calculators to draw the line of best fit to show the trend in real-world data

determine the equation of the line of best fit in order to make predictions

1. The more one studies, their grades will _____.

2. The more a person diets, their weight will _____.

3. The longer one diets, the amount of weight loss will _____.

4. The more a person exercises, their fat mass will _____.

5. The more a person jumps rope, their heart rate will _____.

6. The more a class talks, the teacher's patience will _____.

7. The more a person reads, their vocabulary will _____.

Scatter Plots/Graphs

1. A

positive

correlation: As one quantity

increases

so does the other.

2. A

negative

correlation: As one quantity

increases

the other

decreases

.

3.

No

correlation: Both quantities vary with no clear relationship.

Make a scatter plot of the data in the table. Describe the correlation of the data.

The scatter plot shows a positive correlation

Bird Populations

You have been asked to provide data about the population of red-cockaded woodpeckers in a part of a National Forest in Mississippi. This woodpecker's population has been declining around the state and the Governor wants to know whether or not the protected land of the National Forest has helped the woodpecker's population.

Questions

1. Describe the correlation of the data.

2. If so, what does it mean?

3. What can you tell the Governor?

4. How many active clusters were there in June 1993?

5. What is the equation of the line of best fit?

6. Predict the active clusters by year by 2014?

Calculator Activity

1. Enter the data in the calculator lists.

Place the data in

(L1)

Years Since 1990 (2,3,4, etc.)

(L2)

Active Clusters

STAT #1 Edit

,type values into the lists

2. Set up for the scatter plot

2nd StatPlot

Choose the first Plot, turn ON

Choose first icon

Choose

ZOOM #9 ZOOMStat

3. Determine the line of best fit

STAT

Calc #4

(LinReg [ax+b])

Press

ENTER

4. Graph the line of best fit. Hit

GRAPH

.

Graph

Group Work

Independent Practice

Page 259-261 (Selected Problems) Algebra 1 Glencoe

Closure

Choose 1 problem to answer from higher order thinking skills page 252 #13-16

Homework

Complete Worksheet