binomial probability?

[alinamen]

Not sure Im getting the right answer or if this is even a binomial probability. Please help.

Question.
It is know that 90% of managers of all companies suffer from job related stress. What is the probability that in a sample of 20 of such managers

- exactly 8 suffer
- at most 2 suffer
- at least 3 suffer

expected value
standard deviation

 

[royhaas]

Assume a binomial distribution with n=20, p=.9. Use the formulas in your book or the tables in the back of the book.

 

[alinamen]

n-20
p=.90
x=8
q=.1

exactly 8 suffer from job related stress

I got an answer of .00000000000001

Is this correct?

And then for the others
at most 2
at least 3

Am I supposed to find the probabilities of 0,1,2 and then add to find 2 and 3

Im getting these really large answers - It just seems weird that we would be working with so many zeros