How to set bins correctly when graphing a pdf

I made an histogram with the following code:

histogram(k,'Normalization','pdf')

But when I set an specific number of bins, for example:

histogram(k,15,'Normalization','pdf')

The probabilities stop matching.

I know the exact numbers change given it groups more or less data into one bin, but the whole thing doesn't even add up to one as it should given we're talking about probabilities.

Why is it and how can I fix it????

Answer 1

[the cyclist]

The height of the pdf does not give the probability. The height of the pdf times the width of the interval gives the probability. You've changed the width of the interval (i.e. the bin width).

Use the name-value pair (...,'Normalization','probability') if you want the heights to be the probabilities.