standard deviation of the expected cost per guest?

D

dj s

New member
a product: cost 0.75 mean 5.5 variance 7
b product: cost 0.10 mean 7.2 variance 3
c product: cost 0.05 mean 2.3 variance 1.5

to get expected cost for the average guest : i know how to solve this one: total of (cost * mean) so it is 4.96. but I do not know how to solve the standard deviation of the expected cost per guest here. the answer is 1.99 but i do not know how to do it. please explain some details for me to understand well.

Thanks
 
Back
Top