Using the NHANES data in nhanes.dat, categorize the respondents in three groups: normal, with body mass index (bmxbmi) less than 25; overweight, with 25 ≤ bmxbmi < 30, and obese, with bmxbmi ≥ 30. Also create two age groups, of persons under age 30 and persons at least 30 years old. Create a table of the estimated probabilities for the cross-classification of these two categorical variables, and perform a Rao–Scott test of association and explain.