bmi4: Convert Continuous BMI Values into 4-Level Factor
In dvmisc: Convenience Functions, Moving Window Statistics, and Graphics

Converts a continuous BMI variable into a 4-level factor variable: Underweight if [-Inf, 18.5), Normal weight if [18.5, 25), Overweight if [25, 30), and Obese if [30, Inf).

1	bmi4(x, labels = TRUE)

`x`	Numeric vector of BMI values.
`labels`	If `TRUE`, factor levels are labeled `"Underweight"`, `"Normal weight"`, `"Overweight"`, and `"Obese"`; if `FALSE`, factor levels are `[-Inf, 18.5)`, `[18.5, 25)`, `[25, 30)`, and `[30, Inf)`.