IXL - Variance and standard deviation (Algebra 2 practice)

In the data set below, what is the variance?

If the answer is a decimal, round it to the nearest tenth.

variance (σ²):

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Learn with an example

In the data set below, what is the variance?

If the answer is a decimal, round it to the nearest tenth.

variance (σ²):

The standard deviation (σ) is a measure of how much a data set varies.

The variance (σ²) is the square of the standard deviation.

Step
1:
Compute
the
mean,
μ
.

First add all of the numbers in the data set together. Then divide by the total number of values in the data set.

9 + 8 + 1 + 7 + 8 + 9

Step 2: Compute the variance, σ².

Take each number in the data set, subtract the mean, and square the result. Then take the sum of the squares.

(9 − 7)² + (8 − 7)² + ... + (9 − 7)² = 46

Now compute the variance by dividing the sum above by the total number of values in the data set.

σ²

≈

7.66666

Finally, round to the nearest tenth.

7.66666 → 7.7

To the nearest tenth, the variance, σ², is 7.7.

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