# [R] plotting a set of discrete distributions

Michael Friendly friendly at yorku.ca
Thu Oct 8 15:24:00 CEST 2009

```I have the following data set, representing the the estimated number of
some event (est), when the actual number
was 3, 4, ..., 15.  The numbers in the cells are the observed
*frequencies* of each combination of (actual, estimated),
so each column (a3 -- a15) gives a single discrete frequency
distribution.  Thus, when the actual number was 6,
the estimated values were 5,6,7 with frequencies 7, 120, 20.  The NAs
could be taken as 0s.

> jevons
est a3 a4  a5  a6  a7 a8 a9 a10 a11 a12 a13 a14 a15
1    3 23 NA  NA  NA  NA NA NA  NA  NA  NA  NA  NA  NA
2    4 NA 65  NA  NA  NA NA NA  NA  NA  NA  NA  NA  NA
3    5 NA NA 102   7  NA NA NA  NA  NA  NA  NA  NA  NA
4    6 NA NA   4 120  18 NA NA  NA  NA  NA  NA  NA  NA
5    7 NA NA   1  20 113 30  2  NA  NA  NA  NA  NA  NA
6    8 NA NA  NA  NA  25 76 24   6   1  NA  NA  NA  NA
7    9 NA NA  NA  NA  NA 28 76  37  11   1  NA  NA  NA
8   10 NA NA  NA  NA  NA  1 18  46  19   4  NA  NA  NA
9   11 NA NA  NA  NA  NA NA  2  16  26  17   7   2  NA
10  12 NA NA  NA  NA  NA NA NA   2  12  19  11   3   2
11  13 NA NA  NA  NA  NA NA NA  NA  NA   3   6   3   1
12  14 NA NA  NA  NA  NA NA NA  NA  NA   1   1   4   6
13  15 NA NA  NA  NA  NA NA NA  NA  NA  NA   1   2   2

I'd like to make a plots of (x=actual, y=estimated) and (x=actual,
y=estimated-actual), showing these frequency distributions,
but I'm not sure how to make a plot that shows these distributions
clearly, since the values are frequencies.

To start off, I converted the table to a data frame, excluding the NAs:

jevons.df <- matrix(0, 0, 3)
colnames(jevons.df) <- c("actual", "estimated", "frequency")
for(i in 1:nrow(jevons)) {
estimated <-i+2
for (j in 2:14) {
actual <- j+1
freq <- jevons[i,j]
if (! is.na(freq)) jevons.df <- rbind(jevons.df, c(actual,
estimated, freq))
}
}

giving

> jevons.df
actual estimated frequency
[1,]      3         3        23
[2,]      4         4        65
[3,]      5         5       102
[4,]      6         5         7
[5,]      5         6         4
[6,]      6         6       120
[7,]      7         6        18
[8,]      5         7         1
...

-Michael

--
Michael Friendly     Email: friendly AT yorku DOT ca
Professor, Psychology Dept.
York University      Voice: 416 736-5115 x66249 Fax: 416 736-5814
4700 Keele Street    http://www.math.yorku.ca/SCS/friendly.html