Population and Sample Variance
3 important questions on Population and Sample Variance
How should the variance be interpreted? In other words, what does the size of the variance say about the data? The bigger the variance the.....
The bigger the variance, the more spread out the data is (aka the bigger the distance between the mean and the data points), the smaller the variance, the more clustered the data is around the mean.
Why do we subtract 1 from the sample size (n - 1) in the denominator when we calculate the sample variance?
Abc
When we calculate the variance, we square the difference between individual datapoints and the mean to prevent the positive numbers from cancelling the negatives. But wouldn't that make the variance seem much bigger than it actually is?
When we square we don't just turn a negative into a positive, we also increase its value: a deviation of 2 below the mean (aka -2, turns into a value of 4 when squared.
Yes which brings us to the topic of standard deviation which is essentially the square root of the variance.
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