user78: A block is generated every 10 minutes, on average.
What is the standard deviation of this distribution?
It seems to be a measurable property, not a calculable one.
Is there a chart of the standard dev over time somewhere (should be added to blockchain.info)?

user940: Excluding complications like difficulty changes and temporary blockchain splits, you can model the block generation time as an exponential distribution.
An exponential distribution has a standard deviation equal to the expectancy value. This predicts a 10 minute standard deviation for Bitcoin.

Measuring the actual distribution isn't that easy. While each block contains a timestamp, that timestamp isn't very accurate, and sometimes the time difference between blocks is even negative.
The timestamp doesn't change over the course of a single share, and some miners deliberately use timestamps deviating from the actual time

78: <p>A block is generated every 10 minutes, on average.
What is the standard deviation of this distribution?</p>

<p>It seems to be a measurable property, not a calculable one.</p>

<p>Is there a chart of the standard dev over time somewhere (should be added to blockchain.info)?</p>
 940: <p>Excluding complications like difficulty changes and temporary blockchain splits, you can model the block generation time as an <a href="http://en.wikipedia.org/wiki/Exponential_distribution" rel="nofollow noreferrer">exponential distribution</a>.</p>

<p>An exponential distribution has a standard deviation equal to the expectancy value. This predicts a 10 minute standard deviation for Bitcoin.</p>

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<p>Measuring the actual distribution isn't that easy. While each block contains a timestamp, that timestamp isn't very accurate, and sometimes the time difference between blocks is <a href="https://bitcoin.stackexchange.com/questions/3743/how-can-an-earlier-block-have-a-later-timestamp">even negative</a>.<br>
The timestamp doesn't change over the course of a single share, and some miners deliberately use timestamps deviating from the actual time</p>
