4.4 Scatter Plots

What we will learn Interpret scatter plots Identify correlation Use best fit lines

Needed vocab Scatter plots: graph that shows relationship between two data sets Correlation: relationship between data sets Line of fit: line drawn on a scatter plot that is close to most of data points

Ex. 1 interpreting scatter plots Reading points on the graph How many calories are in the smoothie that contains 56 grams of sugar? 270 How many grams of sugar are in the smoothie that contains 320 calories? 70 What tends to happen to the number of calories as the number of grams of sugar increases? Goes up

Ex. 2 correlation Will be positive, negative, or no correlation

Ex. 3 Finding Line of fit X 1 2 3 4 5 6 7 8 Y 19 15 13 11 10 Finding m: 𝑚= 19−15 1−2 = 4 −1 =−4 Finding b: 19=−4 1 +𝑏 19=−4+𝑏 +4 +4 23=𝑏 Equation: 𝑦=−4𝑥+23 Steps 1. Pick any 2 points 2. Use those points to find slope 𝑚= 𝑦 2 − 𝑦 1 𝑥 2 − 𝑥 1 3. Pick one point and plug into y = mx + b 4. plug in m and b into y = mx + b X 1 2 3 4 5 6 7 8 Y 19 15 13 11 10