82 LASIK surgery complications. 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.