The following table gives the number of heart monitor failures experienced at a local hospital every week. It further shows the probability of each number of heart monitor failures. Determine the expected value of the number of heart monitor failures in a given week. Number of Heart Monitor Failures (xi) Probability p(xi) 1 0.15 2 0.10 3 0.25 4 0.30 5 0.20 

a. Calculate the expected number of failures per week. 

b. Find the standard deviation for the distribution.

 c. If the hospital has one tech on duty at all times and one tech can fix two monitors a week, does the hospital need to staff more techs?

Numbers of Heart Monitor Failures (x) Probability p(x) 1. 0.15 0.1 3 0.25 4 0.3 0.2