Objectives Interpret data in a scatter plot. Find a line of best fit on a scatter plot by inspection.

Glossary Terms scatter plot – shows how two variables relate to each other by showing how closely the data points cluster to a line. Correlation – way to show whether a relationship exists between two variables positive correlation – occurs when both variables increase negative correlation – occurs when both variables decrease line of best fit – a line drawn in a scatter plot that represents a trend and helps you to make predictions

Scientists, such as meteorologists, often look for patterns and relationships between sets of numerical data. The frequency of tornadoes in a certain geographic region or during a certain period of time might show a pattern The scatter plot shows the relationship between the number of tornadoes and the years.

Look at Example 1 on page 38

Use the information from the slide on tornadoes to find a line of best fit Steps for finding a line of best fit. 1. Use a straightedge to model the line. 2. To fit the line to the points, choose your line so that it best matches the overall trend. 3. The line doesn’t necessarily have to pass through any of the points.

Key Skills Draw a scatter plot for data, and determine the correlation. strong positive correlation TOC

Assignment  page 41 – 43 #