import type { DataXY } from 'cheminfo-types';
export interface XYCovarianceOptions {
    /**
     * if true, divide by (n-1); if false, divide by n
     * @default true
     */
    unbiased?: boolean;
}
/**
 * Finds the covariance of the points.
 * @param data
 * @param options
 * @returns the covariance
 */
export declare function xyCovariance(data: DataXY, options?: XYCovarianceOptions): number;
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