The probability of one or more typographical errors on any p

The probability of one or more typographical errors on any page is .002. If a text book contains 1000 pages, compute the probability that

a. There are no typos

b. There are at least 2 typos

Solution

The probability of one or more typographical errors on any page is .002. If a text book contains 1000 pages, compute the probability that

a. There are no typos

n=1000

p=0.002

P(X=x) = (_nC_x) p^x (1-p)^n-x

P(X=0) = (₁₀₀₀C₀) 0.002⁰ (1-0.002)^1000-0

p( x=0) = 0.1351

b. There are at least 2 typos

P( at least 2 error) =1-P( x <2))

=1-( P( x=0)+P( x=1))

=1-(0.1351+0.2706)

=0.5943