Question 270412
Using the following probability distribution for "Numbers of Cars sold" determine the expected value and standard deviation. 
Number of cars sold Probability
5 .15
8 .3
11 .33
17 .22 
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Multiply each car sale number by its probability.
Then add the products to find the expected value.
E(x) = 10.2
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Note: E(x) = u
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To find the standard deviation:
1st: Form (x-u)^2 for each "car sales
2nd: Add those numbers: 78.6
3rd: Divide by N = sum of all the car sales:78.6/41 = 1.92
4th: The standard deviation is the square root of the result of the 3rd step.
s = 1.386
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Cheers,
Stan H.