1. Dot Plots and Distributions
10-3-EXT
Lesson Presentation
Holt McDougal Algebra 1
Holt Algebra 1

2. Objectives Create dot plots.
Use a dot plot to describe the shape of a data distribution.

3. Vocabulary dot plot uniform distribution symmetric distribution
skewed distribution

4. A dot plot is a data representation that uses a number line and x’s, dots, or other symbols to show frequency. Dot plots are sometimes called line plots.
A dot plot gives a visual representation of the distribution, or “shape”, of the data. The dot plots in Example 1 have different shapes because the data sets are distributed differently.

6. Example 1 and 2 :Making a Dot Plots and Shapes of Distribution
Gloria is collecting different recipes for chocolate chip cookies. The table shows the cups of flours needed in the recipes. Make a dot plot showing the data. Determine the distribution of the data and explain what the distribution means.

7. Example 1 and 2 : Continued
Find the least and greatest number in the cups of flour data set. Then use the values to draw a number line. For each recipe, place a dot above the number line for the number of cups of flour used in the recipe. 1 2 3
Amount of Flour Recipes
Cup

8. Example 1 and 2 : Continued
The distribution is skewed to the right, which means most recipes require an amount of flour greater than the mean.

9. Check It Out! Example 1
The cafeteria offers items at six different prices. John counted how many items were sold at each price for one week. Make a dot plot of the data.
Find the least and greatest number in the price data set. Then use the values to draw a number line. For each item, place a dot above the number line for the cost of that item.

10. Check It Out! Example 1 Continued
1.5 2
2.5
3.5
4.5 3 4

11. Check It Out! Example 2
Data for team C members are shown below. Make a dot plot and determine the type of distribution. Explain what the distribution means.

12. Check It Out! Example 2 Continued3 4 5 6
The data distribution is uniform. All team members ran about the same distance.