12. The data given below show the classification of 357 persons by race who visit a physician’s office a certain number of times over a period of one year. The results are shown below. Test, at the 5% level of significance, the hypothesis that the four races are homogeneous with respect to the number of visits to a physician’s office. Find the observed level of significance.

Number of visits White African American Hispanic Asian 0–1 50 34 38 40 2–4 28 35 42 30 5 or more 12 18 16 14 588 13 Analysis of Categorical Data