Understanding the Variance and Standard Deviation

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UNDERSTANDING THE VARIANCE AND STANDARD DEVIATION: A brief lecture on the conceptual development of two very common measures of dispersion, the variance and standard deviation. We use a very small data set, experiment with averaging deviations and then obtaining the mean absolute deviation, then settle on the technique of averaging the sum of squared deviations, which is known as the variance. Then, because we had to square the deviations to avoid them summing to zero, we take the square root of the variance to get the standard deviation. The standard deviation is in the original units of the variable for which it is being computed, and as such, it is usually more common to report the standard deviation than the variance. The standard deviation tells us the average deviation from the mean for a given set of data. For instance, if the standard deviation is equal to 10, we say, "On average, scores differ from the mean by 10 points."

[samanthaedwards]

this is the best explanation I've seen thus far. Thank you.

[nickdodson]

This was extremely helpful for conceptualizing what variance and standard deviation are. I don't really comment on videos, but this was very well done. Thank you!

[regielb]

Is this the population variance? Sample is defined by the numerator is N-1?

[randy]

good but get to the point, you took 20 mins to explain something that could have taken you a max of 7 mins!