Draw Scatter Plots and Best-Fitting Lines Notes 2.6 Draw Scatter Plots and Best-Fitting Lines

Scatter Plot A graph of a set of data pairs (x, y).

Correlations: Positive Correlation: y tends to increase as x increases (positively sloped) Negative Correlation: y tends to decrease as x increases (negatively sloped) Approximately no correlation: The points show no obvious pattern

Describe the correlation:

Describe the correlation:

Approximating a Best-Fitting Line: Step 1: Draw a scatter plot of the data Step 2: Sketch a line that follows the trend most closely (there should be about as many points above the line as below) Step 3: Choose two points on your sketch (they do not have to be actual data points) Step 4: Write the equation of the sketched line

Example: Approximate a best-fitting line: 1 2 3 4 5 6 7 y 280 295 322 395 425 471 511 548 Use your line to predict y when x is 10. Write the equation of your line. Calculate y when x = 10.

Homework: Page 117 3-5, 10-16