import type { ControlChartInput, ControlChartResult } from './types.js';
/**
 * SPC Control Chart Calculator (X-bar/R, X-bar/S, and I-MR)
 *
 * @formula X-bar/R method:
 *   - σ̂ = R̄ / d₂
 *   - UCL_X̄ = X̿ + A₂R̄,  LCL_X̄ = X̿ − A₂R̄
 *   - UCL_R  = D₄R̄,       LCL_R  = D₃R̄
 *
 * @formula X-bar/S method:
 *   - σ̂ = S̄ / c₄
 *   - UCL_X̄ = X̿ + A₃S̄,  LCL_X̄ = X̿ − A₃S̄
 *   - UCL_S  = B₄S̄,       LCL_S  = B₃S̄
 *
 * @formula I-MR method (Individuals & Moving Range):
 *   - σ̂ = MR̄ / d₂  (d₂=1.128 for span-2 moving range)
 *   - UCL_I = X̄ + E₂·MR̄,  LCL_I = X̄ − E₂·MR̄  (E₂=2.66)
 *   - UCL_MR = D₄·MR̄,      LCL_MR = max(0, D₃·MR̄)
 *
 * @reference AIAG (2005). "Statistical Process Control (SPC)", 2nd Ed.
 * @reference ASTM E2587-16. Standard Practice for Use of Control Charts.
 * @reference Wheeler, D. J. & Chambers, D. S. (1992). "Understanding Statistical Process Control".
 *
 * @validation Constants verified against AIAG/ASTM tables for n = 2..25:
 *   n=5: A₂=0.577, D₃=0, D₄=2.114, d₂=2.326
 *
 * @throws {RangeError} At least 2 subgroups are required
 * @throws {RangeError} Subgroup size must be between 2 and 25
 * @throws {RangeError} Subgroup {i} has size {n}, expected {n}
 * @param input - chart type and subgroup data
 * @returns control limits, subgroup statistics, out-of-control points
 */
export declare function controlChart(input: ControlChartInput): ControlChartResult;
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