Question

For a contingency table, which of the following is true?

The observed frequencies must equal the corresponding expected frequencies.

The classification schemes must be independent in order to calculate the expected frequencies.

The number of rows and columns are equal.

In an r x c contingency table, the number of degrees of freedom of the Chi Square statistic is r x c.

Answer 1

The answer is:

The classification schemes must be independent in order to calculate the expected frequencies.

Now, for the contingency table:

• The total number of observed frequencies must equal the total number of expected frequencies. However individual observed frequencies are not equal to the expected frequencies.
• the number of rows and columns can be unequal, we can have 2*3,4*7 contigency tables
• The degrees of freedom is given by (r-1) * (c-1) for r x c contingency table

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