Cumulative Relative Frequency Plots

The cumulative relative frequency plot displays the proportion of the population (or sample) that is less than or equal to each value on the horizontal axis. This plot is also known as the plot of the cumulative distribution function (CDF), or for a sample of data, the empirical cumulative distribution function (ECDF). Thus CDF(x) is the probability that a member of the population in question has a value no bigger than x, that is CDF(x) = Pr(X <= x).

Try it:

    plot(ecdf(Glucose1[,1]))

You can compare two samples by overlaying the ECDF plots, but this turns out to be less effective than directly plotting them against each other, which is known as a "quantile-quantile plot" or "qq plot".