Answer:
Step-by-step explanation:
For this case we can calculate all the questions with the following table:
Class Midpoint(Xi) fi Xi*fi Xi^2 *fi
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0-3 1.5 6 9 13.5
3-6 4.5 6 27 121.5
6-9 7.5 11 82.5 618.75
9-12 10.5 21 220.5 2315.25
12-25 18.5 5 18 1711.25
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Total 49 431.5 4780.25
We can calculate the expected value with the following formula:
And if we replace we got:
We can calculate the sample variance with the following formula:
And replacing we got:
And the deviation would be just the square root of the variance like this: