Simson, Using your example I get most of the values around 0.5, and the ends near 2.3. This is correct for a probability density function; the integral of the pdf over the range of the bins should be 1. This way the pdf values as a function of x don't change with changes in the number of bins, apart from the change in resolution. The probability of a datum appearing in any subrange is the integral of the pdf over that subrange.
Having the sum of the bars add to 1 would be a different sort of normalization. Undoubtedly it has a name, but I don't know what it is. And I don't know why you were getting a y-axis up to 7. Eric Simson Garfinkel wrote: > I'm plotting some histograms with hist() --- well, actually with > ax.hist(), where ax is an axis --- and the "normed=1" isn't working > the way I would expect. > > from pylab import * > > data = sin(arange(0.0,100,.01)) > > fig = figure() > ax = fig.add_subplot(111) > ax.hist(data,bins=50,normed=1,align='center') > show() > > If I do not include normed=1, then the Y scale is an actual count > inside each bin. (The scale goes from 1-1000). > > If I include normed=1, the Y scale goes from 1 - 7. What does that > mean? normed is supposed to make the first result from ax.hist be a > normalized probability distribution. But I would think that it would > change the Y axis to be a probability as well, and it doesn't do that. > > The docstrings do not give any insight, so I looked at the source > code. It certainly *looks* like it's plotting the probability > distribution. But why does the above example give a Y scale going > from 1 to 7? Perhaps I'm showing my lack of statistics here, but I > would think that a strict probability distribution would have the > value of all of the bars adding to 1, > > Sorry to send out so many messages today. I really am trying to > figure this out on my own... > > > > > > ------------------------------------------------------------------------- > Take Surveys. Earn Cash. Influence the Future of IT > Join SourceForge.net's Techsay panel and you'll get the chance to share your > opinions on IT & business topics through brief surveys - and earn cash > http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV > _______________________________________________ > Matplotlib-users mailing list > Matplotlib-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/matplotlib-users ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
