Warm Up Use this class as your data set. List 3 categorical variables and 3 quantitative variables for that can be studied for the data set. Select one categorical variable to collect data. Collect the data for your variable. Make a bar graph.

Section 1.1 Part 2 AP Statistics

Quick graphs Sometimes we would like to get a quick idea of the distribution of a variable from a data set Two of the best graphs are Stemplots Dotplots

Dotplots Horizontal axis with either quanitative scale or categories Each dot represent one data point If more than one data point has the same value, “stack” the dots

Stemplots Each data point is represented by a single number (leaf) associated with a more significant number (stem) Rounding can help the shape of the distribution become more noticeable. Splitting the stems. In half only

Describing Distributions Center: Where is the middle of the data (middle is intentionally vague) Shape: What shape does the data take Are there Outliers Outliers are atypical data points Outliers fall outside the overall pattern of the graph

Describing Shape Uniform Bell Symmetric Skew Bimodal

Uniform 1 13489 2 3 4 5 6 7 8 9 10

Bell 1 2 13 3 135 4 1357 5 135579 6 1355779 7 8 9 10

Skew 1 2 1357 3 1355779 4 135579 5 6 7 13 8 9 10

Bimodal 1 2 1357 3 1355779 4 135579 5 6 13 7 8 9 10

Assignment Read p. 8-12 Do Problems 1.8 – 1.11, The Practice of Statistics Prep for Book discussion