/**
 * 统计相关的函数，主要参考 fast-formula-parser 里的实现
 * https://github.com/LesterLyu/fast-formula-parser
 */
export declare function initial(array: number[], idx?: number): number[];
export declare function rest(array: number[], idx?: number): number[];
export declare function PEARSON(array1: number[], array2: number[]): number;
export declare function VARA(numbers: number[]): number;