standard deviation question

The single point standard deviations are 3,5,10 and 3 for the critical path. What is the standard deviation for the entire path?

A. 10
B. 12
C  14
D. 16

Do you know how to solve this question? 

Thank you

admin's picture

Standard deviation for a series = Square root of the sum of the variances
= SQRT( 9+25+100+9) 
= SQRT(143)
= 11.96 ==~ 12 

These are pure math questions, i dont think PMP real questions will be like this. It will be more around a context and situation. 

This is very stat...