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Key Mathematic Principles for Performance Testers
- brudgers 11y agoGuide to Performance Testing Web Applications home page: https://msdn.microsoft.com/en-us/library/bb924375.aspx https://msdn.microsoft.com/en-us/library/bb924375.aspx
- dwpdwpdwpdwpdwp 11y agoThis is a introduction to fundamental statistics, and not a very instructive one. For example, this is incorrect: "By definition, one standard deviation is the amount of variance within a set of measurements that encompasses approximately the top 68 percent of all measurements in the data set; in other words, knowing the standard deviation of your data set tells you how densely the data points are clustered around the mean." The 68% refers to a rule of thumb for normal distributions, not the definition of standard deviation. https://en.wikipedia.org/wiki/Standard_deviation https://en.wikipedia.org/wiki/Standard_deviation Also, applying this rule will get you in big trouble if your data happens to have a mean that's less than zero: “Data with a standard deviation greater than half of its mean should be treated as suspect. If the data is accurate, the phenomenon the data represents is not displaying a normal distribution pattern.”
- svantana 11y agoNot only that, but saying "the top 68 percent" is flat out wrong. Even if a normal distribution is assumed, it should say "the middle 68 percent" or something to that effect.
- jamisteven 11y agoThings like this are why MS are in the state they are in.
- dang 11y agoPlease don't post unsubstantive dismissals to HN.
- Pamar 11y agounder the "Medians" section: "In the case of the exemplar data sets, Data Sets A and B have median values of 4, and Data Set C has a median value of 1." I didn't bother to check data sets A and B, but C is obviously wrong (Median for C would be 4).