hi, this is the question..

ten batches each containing 20 yoghurt tubs are inspected for rupturing. if the foil is ruptured the tub is rejected. The results of the inspection of the 10 batches are:

batch 1 2 3 4 5 6 7 8 9 10

reject 2 1 0 1 3 1 0 1 1 0

find the exact alpha risk.

i know the answer is 0.0158 but im unsure how to get it since this is a binomial distribution..

this is what i did, i found the upper and lower control limit

UCL = 0.196, LCL = -0.096 -> 0 and mean = 0.05

then using the binomial formula i tried to find P(X>=1), (sorry im not sure how to put in the formula)

n = 20, k = 0, p = 0.05.

so that gave me P(X= 0) = 0.358

P(X>=1) = 1-P(X=0) = 0.6415

which is wrong

please help me