Question

A company has 200 machines. Each machine has 12% probability of not working

Answer 1

If you were to pick 40 machines randomly, the probability that 5 would not be working is

Answer 2

the probability that all would be working is

Answer 3

and the probability that at least one machine would be working is

Answer 4

@mathmale
@Mashy
@magepker728
@magicremix123

Answer 5

@Willie579

Answer 6

@agent0smith

Answer 7

nit sure abt this i'm afraid I think it might be a Binomial Distribution.

Answer 8

I agree: binomial distribution. Look this up and refresh your memory of what a "binomial distribution" involves.
How large is the sample (n)?
What is the probability (p) that a given machine would not be working?
How would you express "the binomial probability that 5 machines out of 40 would not be working?"

Answer 9

12.5% is equal to five out of fourty
@welshfella

Answer 10

More specific hints:

1) n=40 (there are 40 samples)
2) p=0.12 (probability that a given sample will be defective)

3) How would you evaluate a binomial probability? Some calculators have built-in statistical utilities; the TI-84 has several, including binomial probability: binompdf(n,p)

There's a formula for this purpose; look up "binomial probability" on the 'Net

You could calculate the prob. that exactly 3 machines out of 40 would not be working; or you could find the prob. that "at least 2 are not working."

I encourage you to do a bit of research and then come back with some work of your own to discuss, or at least questions about what to do and how to do it.

Answer 11

ok