This is how to create a standard size table:
1. a. Define the min height and the max height
b. Subtract min from max, divide by 2. This is the body measurement height to be used in pattern formulas.
2. List the body measurements you will use.
3. For each circumference-based body measurement:
a. Define the min & max values of the body measurement.
b. Assign min to the base size.
c. Subtract min from max, divide by number of sizes. This is the increment.
4. For each height-based body measurement: (example: height, back waist length)
a. For adults, the same value is filled in for all sizes in the table, increment is 0.
b. For children, there is an age range and growth assumption in the sizing tables. Subtract min from max, divide by number of sizes to find the increment, assign min to base size.
Background data on sizing tables:
Government standard size tables group people into age ranges (e.g. Infants, Boys, Mens).
Then they're separated into height ranges. (Mens Stocky, Mens Regular, Mens Tall)
Child sizes are a bit different than adult sizes because the height ranges are extreme, so the height increases with each size.
Adult sizes have smaller height ranges (usually about 4") so the height for patternmaking is the midpoint of the range, and all sizes are made to fit the midpoint height.
Adult "outliers" of an age/height group have special size tables (e.g. Plus Size Women).