Standard Deviation in One Direction

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Calculating standard deviation for time measurements poses challenges when dealing with a boundary at zero, as negative values are not possible. An average of 4000 microseconds with a standard deviation of 5000 microseconds indicates a skewed distribution, which may not be meaningful in this context. Alternative measures, such as the interquartile range, could provide a better representation of variability when the data is heavily skewed. The concept of a "semi-infinite interval" suggests exploring specific probability distributions that account for one-sided boundaries. It is essential to choose a statistical method that accurately reflects the nature of the data being analyzed.
andrewcheong
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I need to calculate the average time of an event, and I'd like to calculate standard deviation as well. The problem is - there is no such thing as negative time - zero is a boundary - so how does it make sense if the average is 4000us (microseconds) and the stdev is 5000us?

Is there a different measure that I should be using when there is a boundary on one-side, like some sort of a one-directional standard deviation? "Semi-infinite interval" comes to mind, and I Wikipedia'ed such probability distributions for more information, but I'm not sure what to make of it.

Thanks in advance!
 
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Do you have a distribution in mind that actually does that? Sometimes if the distribution is badly skewed the interquartile range gives a better description than the standard deviation.
 

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