Frequency Distributions

• A frequency distribution is a list of data values along with the frequency of occurrence.
• Data is divided into a number of classes
• Each class has
  • A lower class limit, or the lowest value which fits into the class
  • A upper class limit, or the highest value which fits into the class.
  • A class mark, or midpoint, which is (upper+lower)/2
• The class width is the number of different data items which fit into the class.
  • The class width is (upper limit- lower limit) + 1
• Classes must:
  • All be equal width
  • Cover the entire data space
  • Not overlap.
• Do problems 7, 9, 11, 13, 15

Statistical Graphs

• Circle Graphs
• Histograms
• Frequency Polygons
• Stem and leaf display.
• Do Exercises: 9, 12, 15, 23