Question

(1 point) A new computer virus attacks a folder consisting of 200 files. Each file gets damaged with probability 0.2 independently of other files. What is the probability that fewer than 50 files will get damaged?

Answer 1

0.9655

Explanation:

Given that a new computer virus attacks a folder consisting of 200 files

Probability for each file gets damaged = p = probability for success in each trial =
`0.2`

Each file is independent of the other.

Hence X no of files damaged is binomial with n =200 and p = 0.20

Here n denotes the number of files and p probability for success in each trial

We have
`q=1-0.2 =0.8`

Required probability
`=P(X\leq 50)\\=\Sigma _0^(50) 50Cr (0.2)^r (0.8)^(200-r)`

=0.9655