/**
 * Standardization
 */
export default class Standardization {
    /**
     * @param {number} [ddof] Delta Degrees of Freedom
     */
    constructor(ddof?: number);
    _ddof: number;
    /**
     * Fit model.
     * @param {number[] | Array<Array<number>>} x Training data
     */
    fit(x: number[] | Array<Array<number>>): void;
    _m: any;
    _s: any;
    /**
     * Returns transformed values.
     * @param {number[] | Array<Array<number>>} x Sample data
     * @returns {number[] | Array<Array<number>>} Predicted values
     */
    predict(x: number[] | Array<Array<number>>): number[] | Array<Array<number>>;
    /**
     * Returns inverse transformed values.
     * @param {number[] | Array<Array<number>>} z Sample data
     * @returns {number[] | Array<Array<number>>} Predicted values
     */
    inverse(z: number[] | Array<Array<number>>): number[] | Array<Array<number>>;
}