Frequency Distributions and Statistical Graphs

• A frequency distribution is a listing of the observed values and the corresponding frequency for these values.
• This allows us to organize the data to make it easier to understand.
• This is easy for a class with width 1
• Do problem 11 page 743
• For larger classes
  • The classes must all have the same width
  • The classes should not overlap
  • Each piece of data should belong to exactly one class.
• For integer data, the class width is the number of distinct values that can be placed in that class
  • upper class limit - lower class limit + 1
  • The class mark is the (upper limit + lower limit) /2
• Build a frequency distribution for problem 30 page 745
• A histogram is a way to visualize a histogram
  • Label each class with the class mark.
• A frequency polygon is another way to visualize this information.
  • Label with class mark.
  • Connect endpoints to the x axis
• A stem and leaf display is a quick way to draw a histogram.
• A circle graph is a good way to visualize one dimensional data.