I broke out a Barbie, a ruler, and a piece of string.
Barbie's measurements:
Height: 11.75 inches
Head length: 2.00
Neck: .50
Torso: 3.50
Inseam: 5.75
Arm span: 9.75
Arm length (shoulder-fingertip): 4.50
Hips: 4.75
Waist: 2.75
Chest: 4.50
Boobs: 5.00
Head 4.00
So, let's assume that 1 inch = 2 feet
Height: 11.75 inches -- /> 5.875 feet = 5'10"
Head length: 2.00 -- /> 1 = 12"
Neck: .50 -- /> .25 = 3"
Torso: 3.50 -- /> 1.75 = 1'9"
Inseam: 5.75 -- /> 2.875 = 2'10"
Arm span: 9.75 -- /> 4.875 = 4'10"
Arm length (shoulder-fingertip): 4.50 -- /> 2.25 = 2'3"
Hips: 4.75 -- /> 2.375 = 26 inches
Waist: 2.75 -- /> 1.375 = 22 inches
Chest: 4.50 -- /> 2.25 = 27 inches
Boobs: 5.00 -- /> 2.5 = 30 inches (bra size: 32D)
Head 4.00 -- /> 2.0 = 24 inches
So, her head is actually massive in proportion to her height, her arms are 6 inches too short, her legs are slightly longer than average, and she wears smaller than an xx-small at most stores.