2.1 F REQUENCY D ISTRIBUTIONS AND T HEIR G RAPHS CONTINUES …

II. G RAPHS OF F REQUENCY D ISTRIBUTIONS Frequency Histogram: bar graph Horizontal scale is quantitative and measures the data values (class boundaries) Vertical scale measures frequencies of the classes Consecutive bars must touch!  Class Boundaries: the numbers that separate classes without gaps between them. They are needed so the bars CAN touch. Typically, you add and subtract a half unit to the limits.

T URN TO PAGE 38 AND LOOK AT EXAMPLE 3 Now add a class boundaries column to pg45 #23 from yesterday and construct a frequency histogram neatly.

II. G RAPHS OF F REQUENCY D ISTRIBUTIONS CONTINUES … Frequency Polygon: a line graph that emphasizes the continuous change in frequencies Horizontal scale is quantitative and measures the data values (class midpoints) Vertical scale measures frequencies of the classes Graph must start and end at zero, each one class width above or below the appropriate midpoint.

T URN TO PAGE 39 AND LOOK AT EXAMPLE 4 Construct a frequency polygon from the data on pg45 #23 from yesterday neatly.

II. G RAPHS OF F REQUENCY D ISTRIBUTIONS CONTINUES … Relative Frequency Histogram: bar graph Horizontal scale is quantitative and measures the data values (class boundaries) Vertical scale measures relative frequencies of the classes Consecutive bars must touch!  Look at example 5 on page 40…

II. G RAPHS OF F REQUENCY D ISTRIBUTIONS CONTINUES … Ogive aka Cumulative Frequency Graph: a line graph that displays the cumulative frequency of each class at its upper boundary Horizontal scale is quantitative and measures the data values (class boundaries) Vertical scale measures cumulative frequency of each class Graph must start at zero at the first lower limit and end at the total sample size at the largest upper limit

T URN TO PAGE 41 AND LOOK AT EXAMPLE 6 Construct an ogive from the data on pg45 #23 from yesterday neatly.

HOMEWORK Pages 46 – 48 #26 Histogram #34 Ogive #38 Polygon This will take a lot of time. You will need to make a frequency distribution for each then the appropriate graph. PLEASE use graph paper and be neat and accurate!