Human Variability

Sources:

- Age
- Gender
- Occupation - People subconsciously select their jobs based on their body structure
- Racial/Ethnic Differences
- Generational
- Transient Diurnal - variations in body proportions during the day(ex gravity on the spine)

We are not proportional!

Human variability between body parts.

Human Variability

- For normal distributions:

% Value = mean + F x Standard Deviation - X = M + F*x + ADJUSTMENT

Where:

X = % of population less than or equal to you

M = Mean

F = Multiplication factor corresponding to the required percentile

s = standard deviation

Percentile System

80% means that 80% of people are less than you (below or AT)

Statistics

- Central Tendency: Mean, median, mode
- Dispersion: standard dev, max, min, range