Cumulative Frequency Tables and Curves

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Cumulative Frequency Tables and Curves
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Cumulative Frequency
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A Cumulative Frequency Table
Note The scores in the cumulative frequency
column accumulate and the final number should be
the total number of scores you started with.
These are easier to create when the data is
ordered first.
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Cumulative Frequency Graph
Note IB will usually be very specific about the
scale you should use on both the x and y axis.
You will loose a lot of points if you do not
follow their directions exactly!
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Find Q1, Q3 and the interquartile range using the
graph.
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These figures represent the numbers of customers
in a small cinema
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Checking you results for your graph

• IB will specify when you should use your graph to
  approximate the median, Q1, Q3, etc. but you can
  check your estimate by using your calculator and
  inputting mid interval values into L1 and the
  frequency into L2 and running 1VarStats.

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Box Plots
Box Plots are another way to display data that
easily shows Q1, Q2, and Q3. Your calculator can
easily show these for you by doing the following
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Continuous Data and Cumulative Frequency

• When continuous data is given like the weight of
  rocks the way you plot the points changes.

The points to plot on the graph (4.5, 0)
nothing below 4.5 (11.5, 13) 11.5 is the upper
bound (18.5, 28) (25.5, 42 (32.5, 60)