Find the Expected Value and Standard Deviation of a Random

Multiple Choice

Find the expected value and standard deviation of a random variable.
-A small business just leased a new computer and color laser printer for three years.
The service contract for the computer offers unlimited repairs for a fee of $100 a year
Plus a $25 service charge for each repair needed. The company's research indicates that
During a given year 86% of these computers need no repairs, 9% need to be repaired
Once, 4% twice, 1% three times, and none required more than three repairs. The standard
Deviation in the number of repairs for this kind of computer per year is

A) 0.20 repairs.
B) 0.55 repairs.
C) 0.89 repairs.
D) 1.00 repairs.
E) 1.20 repairs.