[R] How is the relation between Frequency and Counts in hist/density defined?

Richard.Cotton at hsl.gov.uk Richard.Cotton at hsl.gov.uk
Mon May 23 16:56:07 CEST 2011


   > In order to do this I can use the relation between count and density, but
   I
   > would like to know if there is a way for me to predict it upfront.
   In the code for hist.default, you'll see the line
   dens <- counts/(n * diff(breaks))
   > Here is an example:
   >
   > set.seed(242)
   > z = rnorm(30)
   > hist_z <- hist(z)
   > hist_z$counts / hist_z$density # the relation is 15
   In your example, n is 30, and the breaks are evenly spaced every 0.5.
   Regards,
   Richie.
   Mathematical Sciences Unit
   [1]HSL
   [2]4D Pie Charts
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