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Degrees of Freedom. Addendum to Chapter 14 Tue, Dec 6, 2005. Goodness-of-Fit Degrees of Freedom. In the goodness-of-fit test for a fair die, we had the following data: Given that the total is 60, how many cells could we fill in arbitrarily and still make the total 60?.
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Degrees of Freedom Addendum to Chapter 14 Tue, Dec 6, 2005
Goodness-of-Fit Degrees of Freedom • In the goodness-of-fit test for a fair die, we had the following data: • Given that the total is 60, how many cells could we fill in arbitrarily and still make the total 60?
Goodness-of-Fit Degrees of Freedom • Use the spreadsheet DegreesOfFreedom1.xls. • We could fill in all but one of the cells, i.e., n – 1 cells. • That would force the value in the last cell to make the total equal to 60. • Therefore, we have n – 1 degrees of freedom.
Independence Degrees of Freedom • In the test of independence, we use the data • Given the row and column totals, how many cells could we fill arbitrarily and still make the row and column totals the same as before?
Independence Degrees of Freedom • Use the spreadsheet DegreesOfFreedom2.xls. • Thus, we can fill in all but one value in each row for all but one row. • That is, we can fill in (cols – 1) values in each row for (rows – 1) rows. • So we have (cols – 1) (rows – 1) degrees of freedom.