bodyfat: percentage of body fat determined by underwater weighing

In mfp: Multivariable Fractional Polynomials

percentage of body fat determined by underwater weighing

Description

A data frame containing the estimates of the percentage of body fat determined by underwater weighing and various body circumference measurements for 252 men.

Source: Roger W. Johnson (1996), ”Fitting Percentage of Body Fat to Simple Body Measurements”, Journal of Statistics Education. Original data are from K. Penrose, A. Nelson, and A. Fisher (1985), ”Generalized Body Composition Prediction Equation for Men Using Simple Measurement Techniques” (abstract), Medicine and Science in Sports and Exercise, 17(2), 189.

Data were supplied by Dr. A. Garth Fisher, Human Performance Research Center, Brigham Young University, who gave permission to freely distribute the data and use them for non-commercial purposes. Note, however, that there seem to be a few errors. For instance, body densities for cases 48, 76, and 96 seem to have one digit in error in the two body fat percentage values. Also note a man (case 42) over 200 pounds in weight who is less than 3 feet tall (the height should presumably be 69.5 inches, not 29.5 inches). Percent body fat estimates are truncated to zero when negative (case 182).

Usage

data(bodyfat)

Format

This data frame contains the observations of 252 men:

case

Case number.

brozek

Percent body fat using Brozek's equation: 457/Density - 414.2

siri

Percent body fat using Siri's equation: 495/Density - 450

density

Density determined from underwater weighing (gm/cm**3).

age

Age (years).

weight

Weight (lbs).

height

Height (inches).

neck

Neck circumference (cm).

chest

Chest circumference (cm).

abdomen

Abdomen circumference (cm) ”at the umbilicus and level with the iliac crest”.

hip

Hip circumference (cm).

thigh

Thigh circumference (cm).

knee

Knee circumference (cm).

ankle

Ankle circumference (cm).

biceps

Biceps (extended) circumference (cm).

forearm

Forearm circumference (cm).

wrist

Wrist circumference (cm) ”distal to the styloid processes”.

Source

e.g. http://lib.stat.cmu.edu/datasets/bodyfat

References

R.W. Johnson (1996). Fitting percentage of body fat to simple body measurements. Journal of Statistics Education [Online], 4(1).

K.W. Penrose, A.G. Nelson, A.G. Fisher (1985). Generalized body composition prediction equation for men using simple measurement techniques. Medicine and Science in Sports and Exercise, 17, 189.

P. Royston, W. Sauerbrei (2004). Improving the robustness of fractional polynomial models by preliminary covariate transformation. Submitted.

Examples

    data(bodyfat)
    bodyfat$height[bodyfat$case==42] <- 69.5   # apparent error
    bodyfat <- bodyfat[-which(bodyfat$case==39),]  # cp. Royston $\amp$ Sauerbrei, 2004
    mfp(siri ~ fp(age, df = 4, select = 0.1) + fp(weight, df = 4, select = 0.1)
                 + fp(height, df = 4, select = 0.1), family = gaussian, data = bodyfat)

mfp documentation built on May 29, 2024, 9 a.m.