# Histogram with added density function

2 views (last 30 days)
Alexander Tollinger on 29 Mar 2020
Edited: Ameer Hamza on 29 Mar 2020
Hey guys,
I am new to Matlab and have a simple question about plots and histograms.
I'd need to create four subplots with each containing a histogram. On every histogram the number of datapoints increases. first histo: 5 datapoints, second histo: 50 datapoints, thrid histo: 500 dp , fourth histo: 5000 dp.
• The datapoints should have an exponential distribution with mean value = 1 (I used exprnd command).
• Additionally I need to add a cdf density function to each subplot. (distribution parameter can also be 1)
clc;
clear all;
close all;
rng('default');
datapoints5 = exprnd(1 , [5,1]);
datapoints50 = exprnd(1 , [50,1]);
datapoints500 = exprnd(1 , [500,1]);
datapoints5000 = exprnd(1 , [5000,1]);
plot(cdf,histogram(datapoints5000));
histogram(datapoints500);
histogram(datapoints50);
histogram(datapoints5);
Hope somebody can help me figure this out,
Best regards,
Alex

Ameer Hamza on 29 Mar 2020
Edited: Ameer Hamza on 29 Mar 2020
Try this:
clc;
close all;
rng('default');
datapoints{1} = exprnd(1 , [5,1]);
datapoints{2} = exprnd(1 , [50,1]);
datapoints{3} = exprnd(1 , [500,1]);
datapoints{4} = exprnd(1 , [5000,1]);
for i=1:numel(datapoints)
ax = subplot(2,2,i);
histogram(datapoints{i});
dist = fitdist(datapoints{i}, 'Exponential');
x_points = linspace(0, ax.XLim(2), 100);
Pdf = pdf(dist, x_points);
Cdf = cdf(dist, x_points);
yyaxis right
hold on
plot(x_points, Pdf, 'r', 'LineWidth', 2, 'DisplayName', 'PDF');
plot(x_points, Cdf, 'b', 'LineWidth', 2, 'DisplayName', 'CDF');
legend
end
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