This calls for a Chi-square goodness of fit test.

The expected values for the null hypothesis are all the same, the total number divided by 12.

The degrees of freedom is 11, which is the number of categories - 1.

One can calculate the Χ^{2} statistic using ∑(Observed - Expected)^{2}/Expected where the sum is over all the categories (in this case, all the months). This will give one a value of 25.213. Then using a Chi-square table with 11 degrees of freedom, one sees a P-value of .0085. Since this is less than .05, one can reject the null hypothesis.

Alternatively, one can use a calculator such as TI-83 or 84 or 89, locate the X^{2} GOF-Test, and, after entering the observed and expected values in two lists and using df = 11, one finds the same results.