2.6 “Scatterplots”Positive Correlation: points line up in a positive slope direction.

Negative Correlation: points line up in a negative slope direction.

No Correlation: points are all over the place.

Scatterplots:

Writing Equations1. A person 25 years old needs

2400 calories of food per day. A person 30 years old needs 2300 calories per day.

A. State the variables

B. Find the slope

C. Find the prediction equation

D. Predict the caloric need of a person 68 years old.

Try This…1. Chef Sam found that after 6

minutes of cooking time, the moisture content of a hamburger was about 48%. After 10 minutes time, the moisture content was about 40%

A. State the variables.

B. Find the slope.

C. Find the prediction equation.

D. Predict the percentage of moisture content after 20 minutes cooking time.

Using Lines of “Best Fit”Use the chart below to:

A. Make a scatterplotB. Draw line of best fitC. Make a prediction

equation.

X = Annual Sales (in thousands)Y = Years of Experience

X 46 35 51 42 33 50 30

Y 6 4 8 5.5 3 7 2.5

Example Continued

1. Set increments2. Plot points3. Draw line of best fit4. Find slope using 2 of the points

PracticeUse the chart below to:

A. Make a scatterplotB. Draw line of best fitC. Make a prediction

equation.

X = Age in YearsY = Blood Pressure

X 35 24 55 48 37 41 30

Y 128 108 145 140 121 132 132

Practice Continued

1. Set increments2. Plot points3. Draw line of best fit4. Find slope using 2 of the points