Answer:
The expected number of appearance defects in a new car = 0.64
standard deviation = 0.93(approximately)
Step-by-step explanation:
Given -
7% had exactly three, 11% exactly two, and 21% only one defect in cars.
Let X be no of defects in a car
P(X=3) = .07 , P(X=2) = .11 , P(X=3) = .21
P(X=0 ) = 1 - .07 - .11 - .21 = 0.61
The expected number of appearance defects in a new car =
E(X) = =
= 0.64
= variation of E(X) =
=
= = 0.8704
standard deviation = =
= 0.93(approximately)