7-4-2

Graphing Single-Variable Statistical Data

Histogram Bar Graph (Histogram)

A histogram shows the frequency (frequency distribution) of each data class as a rectangular bar. Classes are on the horizontal axis, while frequency is on the vertical axis.

IGraph Parameter Settings (page 7-3-3, 7-3-4)

[XList] specifies the list that contains the data to be graphed.[Freq] specifies the frequency of the data.

Tap [OK].

A dialog box like the one shown above appears before the graph is drawn. You can use this dialog box to change the start value (HStart) and step value (HStep) of the histogram, if you want.

The initial HStart and HStep values on the Set Interval dialog box are set in accordance with the Stat Window Auto setting. When On is selected for Stat Window Auto, appropriate values for the graph data are input automatically. When Off is selected, the values that were displayed the last time the Set Interval dialog box was displayed are input automatically.

Med-Box Plot (MedBox)

This type of graph is often called a “Box and Whisker” graph. It lets you see how a large number of data items are grouped within specific ranges.

minX Q1 Med Q3 maxX

LabelMeaning

Description

 

 

 

minXminimumThe data’s smallest value

Q1

First QuartileThe median between minX and Med

 

 

 

MedMedianThe median of all the data values. If you have 13 values, for
example, this is the value at position seven (six values left

 

 

and right).

 

 

 

Q3

Third QuartileThe median between maxX and Med

 

 

 

maxXmaximumThe data’s largest value

 

 

 

• The lines from minX to Q1, and from Q3 to maxX are called “whiskers”.

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