/**
 * Calculate the standard deviation of a list of numbers
 * @param values - List of numbers
 * @returns the standard deviation of the list of numbers, NaN if the list is empty.
 */
export declare function calcStandardDeviation(values: readonly number[]): number;
/**
 * Calculate the mean of a list of numbers
 * @param values - List of numbers
 * @returns the mean of the list of numbers, NaN if the list is empty.
 */
export declare function calcMean(values: readonly number[]): number;
/**
 * Calculate the variance of a list of numbers
 * @param values - List of numbers
 * @param mean - optional mean of the list of numbers, otherwise it will be calculated.
 * @returns the variance of the list of numbers, NaN if the list is empty.
 */
export declare function calcVariance(values: readonly number[], mean?: number): number;
/**
 * Calculate the median of a list of numbers
 * @param values - List of numbers
 * @returns the median of the list of numbers, NaN if the list is empty.
 */
export declare function calcMedian(values: readonly number[]): number;