According to recent studies, 1% of all patients who undergo laser surgery (i.e., LASIK) to correct their

Question:

According to recent studies, 1% of all patients who undergo laser surgery (i.e., LASIK) to correct their vision have serious post-laser vision problems (All About Vision, 2006). In a random sample of 100,000 LASIK patients, let x be the number who experience serious post-laser vision problems.
a. Find E (x).
b. Find Var(x).
c. Find the z -score for x = 950.
d. Find the approximate probability that fewer than 950 patients in a sample of 100,000 will experience serious post-laser vision problems.