Scatter Plots• Scatter Plot: A scatter plot shows the

relationship between TWO data sets.

• This relationship is also called correlation.

• There are three types of correlation:– Positive Correlation– Negative Correlation– No Correlation

Positive Correlation

• The pattern of the dots slants UP and to the right. The two data sets INCREASE TOGETHER.

Negative Correlation

• The pattern of the dots slants DOWN and to the right. When one data set INCREASES, the other DECREASES.

No Correlation

• The dots are spread out. There is no pattern.

Examples:What type of relationship is shown by each

scatter plot?

Positive Negative No Correlation

Determine whether a scatter plot of the data might show a positive, negative, or no correlation.

4) study time, higher grades

5) height, intelligence

6) shoe size, salary

7) age of car, value of car

8) miles per gallon, gas expense

9) education, salary Positive

Negative

No Correlation

Positive

Negative

No Correlation

Determine whether a scatter plot of the data might show a positive, negative, or no correlation.

10) wrist circumference, appetite

11) Birth date, ring size

12) wind-chill, ice cream sales

13) age of tree, number of rings

14) amount of snowfall, shovel sales

15) hair length, hat size

Positive

No Correlation

No Correlation

Positive

Negative

No Correlation

Making a Scatter Plot:

1) Decide which data you will put on the x axis and the y axis.

2) Look at the values for the data you will put on the x-axis. Decide what your scale will be. Label this.

3) Look at the values for the data you will put on the y-axis. Decide what your scale will be. Label this.

4) Plot your points.

Example:

Length of Call (min)

Cost of Call

($)

3 $1.50

5 $2.40

12 $5.55

19 $8.70

23 $10.50

30 $15.00