1. Ch. 3 Histograms In a histogram, the areas of the blocks represent percentages. –Example: Ex. Set B #3 Types of variables: –Qualitative vs. quantitative Discrete vs. continuous –Example: Ex. Set D #1 Cross-tabulation –Example: Ex Set F #1

2. Activity: Martin vs. Westvaco Background How to read the data Bar chart of categorical variables –Bar chart of pay categories by # of employees Stem & leaf plot –Plot of all ages Do Part I of activity How to divide ages (40 or 50 as division)

3. Histogram for age of laid off employees by 10 year intervals –Table (age int., count, percent, percent/year) –Draw the histogram What percent of 53 year olds were laid off? What percent of 53-55 year olds were laid off?

4. BEWARE Usually all intervals are equal, but you must watch out for those that are not created equally. (Ch. 3 Review Exs. #2, 4)