The following is the histogram of the same data (with bar width 5) produced by the TI-83/84
calculator:
Calculator Tip: If you are using your calculator to draw a histogram of data in a list, you might be
tempted to use the ZoomStat command in the ZOOM menu. This command causes the calculator to
choose a window for your graph. This might be a good idea for other types of graphs, but the TI-83/84
does a poor job getting the window right for a histogram. The bar width (or bin width) of a histogram
is determined by XScl and you should choose this to fit your data. The graph above has XScl=5 and,
therefore, a bar width of 5. Xmin and Xmax represent the upper and lower boundaries on the screen. In
this example, they are set at 12.5 and 53.5, respectively.
example: For the histogram below, identify the boundaries for the class intervals.
solution: The midpoints of the intervals begin at 15 and go by increments of 5. So the boundaries
of each interval are 2.5 above and below the midpoints. Hence, the boundaries for the class
intervals are 12.5, 17.5, 22.5, 27.5, 32.5, 37.5, 42.5, 47.5, and 52.5.
example: For the histogram given in the previous example, what proportion of the scores are less