Enter your data for G Chart

Stat > Control Charts > Rare Event Charts > G

Select the option that best describes your data.

Dates of events

Complete the following steps if the measurement data for a G chart are dates in a column.

  1. From Form of data, select Dates of events.
    When your data are entered as dates, Minitab calculates the number of days between events and plots each value on the G chart. When you use dates, you should verify that the number of possible opportunities per day is fairly constant.
  2. In Variables, enter one or more columns of dates. If you enter more than one column, Minitab creates a separate G chart for each column.
In this worksheet, Dates of infection contains the data.
C1-D
Date of infection
4/17
4/24
4/26
5/14
5/16

Number of opportunities between events

Complete the following steps if the measurement data for a G chart are the number of opportunities between events.

  1. From Form of data, select Number of opportunities.
  2. In Method of counting opportunities, select Opportunities between events (0, 1, 2, 3, ...).
    For example, if events occur on the 5th and 8th opportunities, the number of opportunities between events is 2 because 6 and 7 are the opportunities between 5 and 8.
  3. In Variables, enter one or more columns of data. If you enter more than one column, Minitab creates a separate G chart for each column.
In this worksheet, Between events contains the measurement data.
C1-D
Between events
11
10
22
29

Number of opportunities until an event

Complete the following steps if the measurement data for a G chart are the number of opportunities until an event.

Note

If your data are recorded as the number of opportunities until an event, Minitab subtracts 1 from each value to convert the data to number of opportunities between events and plots the converted values on the G chart.

  1. From Form of data, select Number of opportunities.
  2. In Method of counting opportunities, select Opportunities until an event (1, 2, 3, 4, ...).
    For example, if events occur on the 5th and 8th opportunities, the number of opportunities until an event is 3 because 6, 7, and 8 are the opportunities until the event occurs.
  3. In Variables, enter one or more columns of data. If you enter more than one column, Minitab creates a separate G chart for each column.
In this worksheet, Until an event contains the measurement data.
C1-D
Until an event
12
11
23
30
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