/**
 * Computes the arithmetic mean of a numeric iterable, throwing if the sequence is empty.
 *
 * @param src - Source iterable yielding numeric values to average.
 * @returns The arithmetic mean of the input values.
 * @throws Error when the iterable produces no elements.
 *
 * @example
 * ```ts
 * const mean = _average([2, 4, 6]);
 * console.log(mean); // 4
 * ```
 *
 * or using the curried version:
 * ```ts
 * const mean = pipeInto([2, 4, 6], average());
 * console.log(mean); // 4
 * ```
 */
export declare function _average(src: Iterable<number>): number;
/**
 * Curried version of {@link _average}.
 */
export declare const average: () => (src: Iterable<number>) => number;