• Body mass index (BMI) is a value derived from the mass (weight) and height of a person.

• The BMI is defined as the body mass divided by the square of the body height, and is universally expressed in units of kg/m2, resulting from mass in kilograms and height in metres.

• The BMI is a convenient rule of thumb used to broadly categorize a person as underweight, normal weight, overweight, or obese based on tissue mass (muscle, fat, and bone) and height.

The categories are:

< 18: underweight

18-25: normal BMI

25-30: overweight

30-35: obese

35+: morbidly obese

The code I used:

https://rpubs.com/H_L/716867

• I tried to create a BMI caclulator: https://haitaml.shinyapps.io/BMICalculator/?_ga=2.78154196.1321715907.1611496474-8446796.1610212885

and I based the calculation on a simple function mass/height^2

bmi<-function(mass,height)(mass/height^2)
#suppose a women with a weight of 80 kg and a height of 1.6 m

bmi(80,1.6)

[1] 31.25