case0501 {Sleuth2}

Diet Restriction and Longevity

Description

Female mice were randomly assigned to six treatment groups to investigate whether restricting dietary intake increases life expectancy. Diet treatments were:

1. "NP"—mice ate unlimited amount of nonpurified, standard diet

2. "N/N85"—mice fed normally before and after weaning. After weaning, ration was controlled at 85 kcal/wk

3. "N/R50"—normal diet before weaning and reduced calorie diet (50 kcal/wk) after weaning

4. "R/R50"—reduced calorie diet of 50 kcal/wk both before and after weaning

5. "N/R50 lopro"—normal diet before weaning, restricted diet (50 kcal/wk) after weaning and dietary protein content decreased with advancing age

6. "N/R40"—normal diet before weaning and reduced diet (40 Kcal/wk) after weaning.

Usage

case0501

Format

A data frame with 349 observations on the following 2 variables.

Lifetime

the lifetime of the mice (in months)

Diet

factor variable with six levels—"NP", "N/N85", "lopro", "N/R50", "R/R50" and "N/R40"

Source

Ramsey, F.L. and Schafer, D.W. (2002). The Statistical Sleuth: A Course in Methods of Data Analysis (2nd ed), Duxbury.

References

Weindruch, R., Walford, R.L., Fligiel, S. and Guthrie D. (1986). The Retardation of Aging in Mice by Dietary Restriction: Longevity, Cancer, Immunity and Lifetime Energy Intake, Journal of Nutrition 116(4):641–54.

Examples

str(case0501)
boxplot(Lifetime~Diet, width=c(rep(.8,6)), data=case0501,
        xlab="Diet", ylab="Lifetime in months")
summary(subset(case0501, Diet=="NP", Lifetime))