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Suggested answer to exercise: Analyses for qualitative data, 1

Question 1: What is meant by ‘chi-squared = 23.98, P<0.001?’

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Suggested answer

This is the result of the chi-squared test which tests the null hypothesis
that there is no association between *P. alcalifaciens* and foreign travel.
The value 23.98 is the test statistic which will follow a Chi-squared distribution
with 1 degree of freedom if the null hypothesis is true.
P<0.001 tells us that the probability of these data or more extreme data
occurring if the null hypothesis were true is smaller than 0.001
and so we have good evidence that the null hypothesis is not true
and can conclude that an association exists.

Back to Exercise: Analyses for qualitative data.

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Last updated: 27 July, 2009.

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