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

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)

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 year olds were laid off?

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