Assumptions of the Chi Square Test of Independence (2 of 2)
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The formula for chi square yields a statistic that is only approximately a
chi square distribution.
In order for the approximation to be adequate, the total number of subjects should be at least 20.
Some authors claim that the
correction for continuity
should be used whenever an expected cell frequency is below 5. Research in statistics has shown that this practice is not advisable. For example, see:
Bradley, Bradley, McGrath, & Cutcomb (1979)
.
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