WEBVTT

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Here is the problem: Find the population standard deviation of 2, 4, 4, 4, 5, 5, 7, 9.

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Treat the data as the entire population (divide by n).

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Find the mean.

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Square each deviation from the mean.

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Add the squared deviations.

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Divide by n to get the population variance.

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Take the square root.

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So the answer is σ equals 2.

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Standard deviation measures how spread out the values are around the mean. A small value means the data are clustered near the mean.

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Variance equals 4, and 2 squared equals 4.

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Sample SD for comparison: 2.138089935.