Peter I. answered • 06/27/13

Tutoring for Scholastic Excellence in Business and Science

The first thing you do is to rearrange the numbers.

Then, multiply the 1st column by the 2nd column to get the 3rd column

Next, you add up the 3rd column to get the mean.

X P(X = x) (x * Px) x - µ (x - µ) ^2 (x- µ) ^ 2* p(X = x)

4 0.1 0.4 4 - 5.7 2.89 0.289

5 0.3 1.5 5 - 5.7 0.49 0.147

6 0.45 2.7 6 - 5.7 0.09 0.0405

7 0.10 0.7 7 - 5.7 1.69 0.169

8 0.05 0.4 8 - 5.7 5.29 0.2645

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Total = **5.7 (mean, µ)** Total = **0.91 (variance**)

To calculate the standard deviation, develop columns 4, 5, and 6.

Finally, you sum up column 6 to arrive at the variance.

Remember that Standard Deviation is the Square root of Variance

Therefore, square root of 0.91 = **0.95 (std. dev.)**

If you abide by the above methodology, the sky is definitely the limit for you. Thank you.