METHOD VALIDATION · PRECISION

Precision Calculator

Enter replicate measurements for one or more conditions (days, analysts, instruments). The calculator computes per-group SD and RSD (repeatability) and the combined intermediate precision using a pooled-variance decomposition — matching the Battery Method Validation walkthrough.

Analyte & Combined Acceptance

Analyte Unit Max Combined RSD (%) Intermediate precision criterion

PASS

Repeatability Acceptance

Max RSD (%)

Replicate Values (wt%)

n = 6

#Value

Values & Deviations

#	Value (wt%)	Dev from x̄
1	48.120	+0.0200
2	48.080	-0.0200
3	48.190	+0.0900
4	48.040	-0.0600
5	48.110	+0.0100
6	48.060	-0.0400

n = 6 x̄ = 48.100 wt%

SD = 0.0533 wt%

RSD = 0.11% (≤ 2%) ✓

PASS

Repeatability Acceptance

Max RSD (%)

Replicate Values (wt%)

n = 6

#Value

Values & Deviations

#	Value (wt%)	Dev from x̄
1	48.050	-0.0500
2	48.140	+0.0400
3	48.090	-0.0100
4	48.180	+0.0800
5	48.020	-0.0800
6	48.120	+0.0200

n = 6 x̄ = 48.100 wt%

SD = 0.0590 wt%

RSD = 0.12% (≤ 2%) ✓

Strip Chart — Ni (wt%)

Bars = ±1 SD · Diamonds = mean · Dots = individual reps

Combined Intermediate Precision — Ni (wt%)

PASS

Pooled-Variance Decomposition

SS_within = Σ (n_i−1)·SD_i² = 0.031600

SS_between = Σ n_i·(x̄_i−x̄_G)² = 0.000000

Pooled variance = (SS_within + SS_between) / (N−1) = 0.002873

Grand Mean

48.100 wt%

Combined SD

0.0536 wt%

Combined RSD

0.11% (≤ 3%) ✓

Combined intermediate precision criterion met. Combined RSD = 0.11% ≤ 3%. Between-condition variability is negligible — precision is dominated by within-run repeatability.

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