Spell-checking software catches "nonword errors" which result in a string of letters that is not a word, as when "the" is type "teh." When undergraduates are asked to (without spell checking), the number X of nonword errors has the following distribution:

errors(X): 0,1,2,3,4

probability : .29, .19, .13, .12, ---

a)In the table shown above the probability of exactly 4 errors is not given. Using what you know about probability distributions, what is the probability of exactly 4 errors?

b)What is the probability of at least 1 nonword error?

c)Find the expected value of this distribution. How many nonword errors can you expect from a typical paper written under the previously mentioned conditions?