Change histogram y-axis to percentage [R2017b]

Good morning,

I have used the histogram function to get a plot of a histogram. Specifically, for presentation, I would actually only like to have the probability value as a percentage plotted against the bins. For this I have used the histogram properties 'Normalisation' set to 'probability' and 'DisplayStyle' set to stairs'. I need the y-axis as a percentage. I see that I cannot access the histogram.Data values as they are read only and therefore I cannot modify them. I was simply going to multiply them by 100.

Is there anyway to plot this data from the histogram function as: 1) a line plot; 2) with y-axis values as percentage so that when I zoom in and out the percentage also re-scales rather than just setting yticklabels.

Cheers, TJ

Answer 1

[Star Strider]

I’m not certain what you’ve already done.

The 'YTick' values are available, and you can modify them as you would with any other usual axis object.

Example —

d = randn(1, 1000);                         % Create Data

figure
histogram(d, 50, 'Normalization','probability', 'DisplayStyle','stairs')
figure
histogram(d, 50, 'Normalization','probability', 'DisplayStyle','stairs');
ytix = get(gca, 'YTick')
set(gca, 'YTick',ytix, 'YTickLabel',ytix*100)

Compare the two figures to see the result of recalculating the 'YTick' values in the second histogram.

Answer 2

[Andreas Vester]

Browse the MATLAB documentation for 'yticks' and 'yticklabels'.

One solution might be as follows:

yticklabels(yticks*100)

[Lisa Kinsale]

Thank you, this works,

Additionally do you know how to display the percentage sign (%) on the new yticklabels?

[Augusto Gabriel da Costa Pereira]

Here:

ytickformat('percentage');

Answer 3

[Tony Castillo]

Hi Sir,

I have plotted a histogram I wonder if is possible to set another axis in the plot like the one in the figure attached, would you mind telling me how to do it, please?.

[Mahmoud Alkhateb]

Hi Tony!

if you want to have the relative frequency on the y-axis (precentage).

You can try this one:

Let's say you have this:

x = let's say you have 30 values bewteen 0 and 25.

L = define the bins you wanna have. e.g. L = 0:5:25; %% this will give you bins that are equal to five starting at 0 and ending at 25.

Now you can plot your histogram as follows

bar (x, histc(x,L)/30, 'histc') %% dividing by 30 which is the number of the total values you have, will give you the relative frequency to evey bin.

Let's say you got 6 values between 0 and 5 (the first bin), what you will get at the y-axis for this bin is 6/30 which is 0.2 (which is 20 %).

I hope this helped!