export interface StatisticsSnapshot {
    /** Number of values represented by this snapshot. */
    count: number;
    /** Sum of all represented values. */
    sum: number;
    /** Smallest represented value. */
    min: number;
    /** Largest represented value. */
    max: number;
    /** Arithmetic average of all represented values. */
    mean: number;
    /** Sample variance, calculated with `count - 1` as the divisor. */
    variance: number;
    /** Estimated median from `samples`: about half of the observations are at or below it. */
    p50?: number;
    /** Estimated 95th percentile from `samples`: about 95% of the observations are at or below it. */
    p95?: number;
    /** Bounded random sample used to estimate percentiles without retaining every value. */
    samples?: number[];
}
export declare const DEFAULT_STATISTICS_RESERVOIR_SIZE = 256;
export declare class StreamingStatistics {
    private readonly _reservoirSize;
    private readonly _random;
    private _count;
    private _sum;
    private _min;
    private _max;
    private _mean;
    private _m2;
    private readonly _reservoir;
    constructor(_reservoirSize?: number, _random?: () => number);
    add(value: number): boolean;
    merge(snapshot: StatisticsSnapshot): boolean;
    snapshot(): StatisticsSnapshot;
    private _reservoirAfterAdd;
    private _mergedReservoir;
}