1. 4.4 Scatter Plots

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

3. 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

4. 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

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

6. 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
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