Standard Deviation

In statistics and probability theory, the standard deviation (SD) (represented by the Greek letter sigma, σ) shows how much variation or dispersion from the average exists. A low standard deviation indicates that the data points tend to be very close to the mean (also called expected value); a high standard deviation indicates that the data points are spread out over a large range of values.The standard deviation of a random variable, statistical population, data set, or probability distribution is the square root of its variance. It is algebraically simpler though in practice less robust than the average absolute deviation.
Posts about Standard Deviation
  • 3 Key PPC Metrics Are Lying To You. Find Out How

    …) the average. To fully understand what is happening with our ads, we need to know more about where they are being shown. At the very least we want to see: The standard deviation. This tells us how far from the average our ads were distributed. Were our impressions clustered around the position AdWords is showing or did we have impressions in a much…

    Sam Owen/ Search Engine Landin Paid Search- 22 readers -
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