How do I normalize the Y-axis of histogram between 0 and 1?

Question

I need to normalized the Y-axis of an histogram between 0-1.

This is a part of my data.frame:

1.8064 2.2016 2.4506 2.1828 2.1171 1.9308 2.1707 2.1885
2.2310 2.2400 1.9115 2.1527 2.0934 1.7989 2.2144 2.0091
1.9248 2.2038 1.9676 1.9224 1.9502 1.7990 2.0824 2.1300
2.0095 2.0341 1.8433 1.8361 1.9958 1.8243 2.0397 2.0482
2.1143 2.2627 1.7620 1.7561 1.9490 1.9803 1.9336 2.2511
2.2377 2.5414 1.7867 1.6618 2.5090 1.8325 2.0212 2.1616
2.3476 2.1878 2.0469 1.7508 2.2969 1.7939 2.0291 2.0721
2.3534 2.0932 2.3502 1.9960 2.0710 1.9923 1.7787 1.9772
2.2607 2.1504 2.3685 2.1148 2.1961 1.7738 1.8405 2.0135
2.2411 1.9916 2.4726 2.0347 2.0751 1.7570 1.8874 1.9385
2.1913 1.8981 2.2441 2.3068 2.1198 2.1484 1.8056 1.7747
2.0842 1.8750 2.3023 2.1204 1.8972 2.1534 1.8028 1.9401
2.2105 1.9618 2.2472 1.9656 2.3098 1.9771 1.9520 1.8627
2.2863 1.9959 2.1781 1.9544 1.9281 1.9286 1.9699 2.0330
2.1987 2.0583 2.0953 2.0206 2.1148 2.3789 1.7052 1.9145
2.0513 2.0850 1.9810 2.4943 1.9120 2.2209 1.9461 2.0882
2.0049 2.0416 1.9303 2.3681 1.8974 2.0054 1.9261 1.9097
1.6882 2.1196 1.8641 2.3600 2.0931 1.7641 2.1131 1.7748
1.8840 1.7604 1.7664 2.2000 2.0055 1.8229 1.9871 1.9168
1.7340 1.9656 1.8480 2.0523 1.9950 1.8716 1.9206 1.7786

And this is what I'm doing currently:

for (i in data){
  x <- i

  h<-hist(x, plot = FALSE)
  h$density = h$counts/sum(h$counts)

  plot(h, col="red", xlim = c(0,max(data)))}

But I get this picture:

But what I really want is something like this (Y axis between 0-1):

Use scale() function (http://www.inside-r.org/r-doc/base/scale) — Alejandro Alcalde, Jul 05 '16 at 11:17
@algui91 scale where?. I don't want to scale my dataframe, I want to scale the frequency. Is there any way to do this? I'm a bit of a newbie in R — Enrique, Jul 05 '16 at 11:25
Check out this answer: http://stackoverflow.com/questions/15215457/standardize-data-columns-in-r — Alejandro Alcalde, Jul 05 '16 at 11:27
@algui91 Thank you. I checked but my doubt has not been resolved. — Enrique, Jul 05 '16 at 11:48
If I am not wrong, `scale`, althought its name, does a normalization between [-1,1] of the data. It gives you a normal distribution of mean 0 and sd = 1. Is not that what you want? — Alejandro Alcalde, Jul 05 '16 at 11:52
@algui91 Yes, but I don't want to scale my X-axis, I want to scale my Y-axis between 0-1. — Enrique, Jul 05 '16 at 12:02

score 1 · Accepted Answer · edited May 23 '17 at 12:14

1

To scale your Y between [0,1] you could use what flodel suggested in this answer

maxs <- apply(a, 2, max)
mins <- apply(a, 2, min)
scale(a, center = mins, scale = maxs - mins)

But modifying that code to use only your y column:

maxs <- max(y)
mins <- min(y)
scale(y, center = mins, scale = maxs - mins)

Hope it helps

edited May 23 '17 at 12:14

Community

1
1

answered Jul 05 '16 at 12:07

Alejandro Alcalde

5,990
6
39
79

score 0 · Answer 2 · answered Jul 05 '16 at 14:16

0

Just divide each observation by the max to normalize the data to 1.

But the question remains, why? If the y-axis is normalized 0-1, it implies probability, which this clearly is not.

answered Jul 05 '16 at 14:16

milkmotel

402
4
13

How do I normalize the Y-axis of histogram between 0 and 1?

2 Answers2