SOLUTION: Are we influenced to buy a product by an ad we saw on TV? National Infomercial Marketing Association determined the number of times buyers of a product watched a TV infomercial bef

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Question 1022932: Are we influenced to buy a product by an ad we saw on TV? National Infomercial Marketing Association determined the number of times buyers of a product watched a TV infomercial before purchasing the product. The results are shown here: Compute the mean of the distribution.
Part 2: compute the standard deviation of the distribution

Number of times watching Infomercial
1
2
3
4
5
all times more will be counted as 5

Probability product is purchased
27%
31%
18%
9%
15%
Compute the mean of the distribution.
Answer by robertb(5830) About Me  (Show Source):
You can put this solution on YOUR website!
Mean = E(X) = 1*0.27+2*0.31+3*0.18+4*0.09+5*0.15 = 2.54.
Standard deviation = sqrt%28Var%28X%29%29+=+sqrt%28E%28X%5E2%29+-+%28E%28X%29%29%5E2%29
=
=sqrt%288.32+-+6.4516%29+=+sqrt%281.8684%29+=+1.367, to three decimal places.