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From: "Mastaneh " <mtorkama@iupui.edu>
Newsgroups: comp.soft-sys.matlab
Subject: Histogram and Normality test
Date: Wed, 6 Aug 2008 17:18:02 +0000 (UTC)
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Dear all,

I have a 2^18-length data, sampled at 48 kHz with a 16-bit 
ADC. The histogram is very close to the normal 
distribution, but the data always fails the normality 
hypothesis tests. 
When plotting the histogram with 1000 bins, there are 
various spikes in the figure. I know reducing the number of 
bins help get a smoother curve, but am I correct in 
assuming that these spikes are the reason the tests fail? I 
mean, the test needs to average the spike amplitudes to get 
the estimated distribution, so the result doesn't have the 
same moments as the original sample. 

Thanks for any explanation,
Mastaneh