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I have two examples of a Cullen and Frey graph (obtained using the fitdistrplus package in R). The first is from this question, and the second is from some data I have. I don't understand what the use of the bootstrapped values are. In the first graph, do they simply confirm that the empirical bootstrap sample have observed kurtosis and skew that match that of a beta distribution, thus giving support to the hypothesis that the original data is beta distributed? What about in my data where the bootstrapped values are all over the graph. What am I meant to conclude?

enter image description here

enter image description here

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Alex
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  • Can you graph either qqnorm or ecdf? Can you list numeric summary statistics for your data? What was the text output of the descdist function? – EngrStudent May 22 '17 at 23:52
  • Why would doing these things help me understand what the bootstrapped values do? – Alex May 23 '17 at 01:37
  • They are alternative pictures of the data that can help show the distribution. Think of each tool a a foggy window, but with multiple windows you can get a better picture. Ecdf, qqnorm, this, and others are tools, hammers, but not every problem is a nail. They will show not only the tails, but the center. They can show modality. They are also frameworks for determining the nature of the distribution. – EngrStudent May 23 '17 at 12:31
  • I see. But using your analogy, I am really asking about how to use a hammer. I ended up choosing a distribution for my data but I am still curious to know how I am meant to interpret the bootstrapped kurtosis and skew values. – Alex May 23 '17 at 23:22
  • I am still figuring out this graph, for my own uses too. My best guess is to look at the blue point, my distro, and what it is near. If it is on one of the lines, such as gamma or lognormal, then it can be gamma, lognormal, or weibull. I think (my guess) that the bootstrap gives you a heuristic sense of where the point could be, and helps pick nearer vs. farther points. That is why I asked my related question about how to plot a 2d nonparametric density on the bootstrap values. – EngrStudent May 24 '17 at 00:37

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