Steps in Calculating chi-square test for
contingency tables
1.
Start with the observed frequency table
(fo) and
2.
Calculate marginal sums (row sums, column
sums, etc.)
3.
Calculate marginal proportions
4.
Multiply marginal proportions together to
get estimated cell proportions
5.
Multiply result in (4) by total number. These
are expected frequencies (fe)
6. Calculate for each cell of the table the chisquare statistic
chi-square = (fo-fe) 2 /fe
7.
Sum up all the of individual chi-squares to
yield the chi-square for the table.
8.
The degrees of freedom are number of rows
(nr) minus 1 times the number of columns
(nc) minus 1
Degrees of freedom = (nr-1) x (nc-1)