When julia is writing a first draft, there is 0.7 probability that there will be no spelling mistakes on a page. one day, julia writes a first draft that is 4 pages long. assuming that julia is equally likely to have a spelling mistake on each of the 4 pages, what is the probability that she will have no spelling mistakes on at least one of them?

The required probability is  given by, 0.9919.

Step-by-step explanation:

Let, X be the random variable denoting the no. of pages among those 4 pages which Julia writes where she makes no spelling mistake.

clearly,

X Binomial (4, 0.7)

So,      P(X = x) =

                            [when  x = 0, 1, 2, 3, 4]

                         = 0 otherwise

According to the question, we are to find out  P(X ≥ 1) .

Now, P(X ≥ 1)

     = 1 - P(X = 0)

     =

     =

     = 0.9919

So, the required probability is  given by, 0.9919