/**
 * Calculates the average of an array of values
 * @param values Array of values
 * @param sum Optional pre-calculated sum
 * @returns Average value or null if array is empty
 */
export declare const calculateAverage: (values: number[], sum?: number) => number | null;
/**
 * Calculates percentile using Hyndman and Fan type 7 linear interpolation.
 * @param sortedValues Array of sorted values
 * @param percentile Percentile to calculate (0-100)
 * @returns Interpolated percentile value
 */
export declare const calculatePercentile: (sortedValues: number[], percentile: number) => number | null;
/**
 * Finds the minimum value in an array
 * @param values Array of values
 * @returns Minimum value or null if array is empty
 */
export declare const calculateMinimum: (values: number[]) => number | null;
/**
 * Finds the maximum value in an array
 * @param values Array of values
 * @returns Maximum value or null if array is empty
 */
export declare const calculateMaximum: (values: number[]) => number | null;
/**
 * Calculates the standard deviation of an array of values
 * @param values Array of values
 * @param mean Optional pre-calculated mean
 * @returns Standard deviation or null if array is empty
 */
export declare const calculateStandardDeviation: (values: number[], mean?: number) => number | null;