RSS tolerance analysis replaces the linear sum with a geometric one:
The Root Sum Square (RSS) method is a statistical tolerance analysis technique. Unlike the "Worst-Case" (WC) method, which assumes all dimensions are simultaneously at their extreme limits, RSS assumes that dimensions follow a normal distribution (Bell Curve) and are independent of one another. rss tolerance analysis
$$T_RSS = \sqrt0.10^2 + 0.05^2 + 0.15^2 + 0.10^2$$ $$T_RSS = \sqrt0.0100 + 0.0025 + 0.0225 + 0.0100$$ $$T_RSS = \sqrt0.0450$$ $$T_RSS = \pm 0.212 \text mm$$ RSS tolerance analysis replaces the linear sum with
The total assembly tolerance is calculated by taking the square root of the sum of the squares of individual tolerances: rss tolerance analysis
Where $T_assembly$ is the total assembly tolerance and $T_i$ is the individual component tolerance.