Answer:
The probability that the reporter made no typographical errors for the 3-page article is 5%.
Step-by-step explanation:
Let <em>X</em> = number of typographical errors made by the writer.
The average umber of mistakes mad by the writer every page is, <em>E </em>(<em>X</em>) = 1.
The random variable <em>X</em> is defined as finite number of occurrence of a certain activity in a fixed interval of time.
A Poisson distribution is used to describe the distribution of occurrences in a certain interval.
Thus, the random variable <em>X</em> follows a Poisson distribution.
It is provided that the writer has landed a 3-page article in an important magazine.
Then the average number of mistakes in the 3 pages is:
<em>λ</em> = 3 × E (X) = 3 × 1 = 3.
The probability mass function of the Poisson random variable <em>X</em> is:

Compute the probability that the writer makes no mistake in a 3-page article as follows:

The probability that the writer makes no mistake in a 3-page article is 0.05.
Thus, the probability that the reporter made no typographical errors for the 3-page article is 5%.