Variance in the Slope of the Frailty Index. The Bootstrapping of the frailty index. The frailty index was created and plotted 1000 times, each time randomly picking 80% of the variables of the index. Twenty iterations are shown here. The experimental and best fit regression lines of the average index values are shown in the baseline (red) and follow up (blue).
Searle et al. BMC Geriatrics 2008 8:24 doi:10.1186/1471-2318-8-24