MATLAB: Overlaying histogram with lines and not bars

histogram

Hi all.

Can somebody tell me how to plot histograms with lines instead of bars in Matlab?

Thanks.

Best Answer

did you want something like

x = 5+2*randn(1000,1);
h = histc(x,(0:9));
stem(h,'b')

or like

plot(h,(0:9))

Related Solutions

MATLAB: Normalized distribution for histogram

If you have the Statistics Toolbox, you might find the dfittool distribution fitting tool quite useful.

doc dfittool

If not, you can normalize a histogram by scaling the counts in each bin. With the normalized counts, you can plot both the normalized histogram and your curve. The trick is to identify the appropriate scaling factor.

Here is some example code where I plot the normal probability with the normalized histogram data:

% Arbitrary data generation and statistics
dataVec = randn(1000,1);
muData = mean(dataVec);
stdData = std(dataVec);
% Defining the bin centers
binStep    = 0.1;
binCenters = -5:binStep:5;
% Compute the histogram scaling factor. (If all histogram counts are in a
% single bin, the probability = 1)
binCount   = histc(dataVec,binCenters);
probScale  = sum(binCount)*binStep;
% Plot the normalized histogram and change the bar color for line
% visibility
histHandle = bar(binCenters,binCount/probScale,'hist');
set(histHandle,'FaceColor',[1,1,1]); 
hold on;
% Overlay the distribution fit on the histogram
x = binCenters;
y = normpdf(x,muData,stdData);
plot(x,y);
xlabel('Data');
ylabel('Probability');

Hope this helps to get you started!

MATLAB: Histogram

There is a ksdensity function that can produce a kernel-smooth density estimate. The issue is that it produces a density (integrates to 1) and the histogram is not a density (bar heights sum to 1). You could figure out the area of the histogram and re-scale the ksdensity values. Alternatively, here's a way to create the histgram, normal curve, and kernel density separately:

x = [randn(100,1); 4+randn(50,1)];
[hts,ctrs] = hist(x)
bar(ctrs,hts,'hist')
area = sum(hts) * (ctrs(2)-ctrs(1))
xx = linspace(-3,7);
hold on; plot(xx,area*normpdf(xx,mean(x),std(x)),'r-')
f = ksdensity(x,xx);
plot(xx,area*f,'g-')
hold off

Best Answer

Related Solutions

MATLAB: Normalized distribution for histogram

MATLAB: Histogram

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