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Results tagged with standard-deviation
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user 88965
In Probability and Statistics, the standard deviation of a statistical population or data set is a measure of how much variation or dispersion exists from its average value. It is defined as the square root of the variance. Use this tag alongside (statistics).
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Why does variance divide by $n-1$? [duplicate]
The variance is: $$\dfrac{\sum_{i=1}^{n}(x_i-\bar x)^2}{n-1}$$
I read that $n-1$ is used instead of just $n$ when we are measuring the variance of a sample taken from a bigger population. I don't …
- 5,053
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Why is variance squared?
The mean absolute deviation is:
$$\dfrac{\sum_{i=1}^{n}|x_i-\bar x|}{n}$$
The variance is: $$\dfrac{\sum_{i=1}^{n}(x_i-\bar x)^2}{n-1}$$
So the mean deviation and the variance are measuring the …
- 5,053
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question about Mean absolute deviation formula
$$\frac{\sum_{i=1}^{n}(x_i-\bar x)}{n}$$
This method will not work for calculating the mean deviation.
Instead we have:
$$\frac{\sum_{i=1}^{n}|x_i-\bar x|}{n}.$$
I'm not quite understanding why w …
- 5,053