Answer:
The overall standard deviation, s = 6.46 %
Given:
Sampling variance,
Analytical variance,

Solution:
Variance additive is given by:
(1)
where
s = overall variance
Also, we know that:
Standard Deviation,

Therefore the standard deviation of the sampling, analytical and overall sampling is given by taking the square root of eqn (1) on both the sides:


s = 6.46 %