π Chi squared test
What is the chi squared test?
Null hypothesis
The chi-squared value
How to carry out the chi squared test
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What is the chi squared test?
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The chi-squaredΒ (c2) test is a measure of expected frequency versus observed frequency to determine how closely aligned they are; whether what is observed would be expected or whether it is different to what would be expected.
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Null hypothesis
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The default expectation is the null hypothesis which states that no difference exists between the things we are experimenting with, observing or comparing and their default, or control state.
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The chi-squared value
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The chi-squared value we obtain from the chi-squared test is put against a probability scale. The probability refers to the probability that for a given chi-squared value (which is defined by how different our observation is from what we would expect), what we observe really is different to what we expect to a significant extent that enables us to reject the null hypothesis.
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For example, our expected values for the eye colour of 154 flies in a population would be…