1) BMI calculation
Subject A B C
Age 57 30 18
Gender Male Male Male
heigth 70 in 72 in 68
70 * 2.54 = 177.8cm 72*2.54=182.88cm 68*2.54=172.72 cm
weight 165 lb 190 lb 185 lb
165/2.2046=74.8kg 190/2.2046=86.2kg 185/2.2046=83.9kg
BMI 74.8*10,000 86.2*10,000 83.9*10,000
----------------- = 23.7 ----------------- = 25.8 ----------------- = 28.1
(177.8)^2 (182.88)^2 (172.72)^2
2) Weight status
Subject A: 18.5 ≤ 23.7 ≤ 24.9 => Considered Ideal
Subject B: 20.5 ≤ 25.8 ≤ 29.9 => Considered Overweight
Subject C: 20.5 ≤ 28.1 ≤ 29.9 => Considered Obese
Ideal weight range
Inequality
w * 10,000 18.5*h^2 24.9*h^2
18.5 ≤ --------------- ≤ 24.9 => ------------- ≤ w ≤ -------------
h^2 10,000 10,000
Subject A: h = 177.8 cm =>
18.5*(177.8)^2 24.9*(177.8)^2
------------------- ≤ w ≤ ---------------------
10,000 10,000
58.5 kg ≤ w ≤ 78.7
Subject B: h = 182.88 cm
18.5*(182.88)^2 24.9*(182.88)^2
------------------- ≤ w ≤ ------------------------
10,000 10,000
61.9 kg ≤ w ≤ 83.3
Subject C:
18.5*(172.72)^2 24.9*(172.72)^2
--------------------- ≤ w ≤ ---------------------
10,000 10,000
55.2 kg ≤ w ≤ 74.3 kg
3) Is BMI an appropiate measure of health?
Pros:
* it is quick and easy to calculate, so it provides a prompt measure.
Cons:
* It is not accurate.
* It leaves out specific conditions of the person: genetic and fitness.
I like that it provides a standardization to compare the status of different persons based on an objective measure, but you need to include other factors: age, gender, build, fat %, activities performed, among others. So, I am in favor of using it only like a factor but you need to use other additional measures.