import math

def stats_on_signal(x, N):
    NN = len(x)
    if N <= 0 or N >= NN:
        raise ValueError("N должно быть > 0 и < количества отсчётов сигнала")

    part1 = x[:N]
    part2 = x[N:]

    M1 = sum(part1) / len(part1)
    M2 = sum(part2) / len(part2)

    def sample_var(data):
        n = len(data)
        m = sum(data) / n
        return sum((v - m) ** 2 for v in data) / (n - 1)

    C1 = sample_var(part1)
    C2 = sample_var(part2)

    return M1, M2, C1, C2, NN


def process_file(filename, N):
    values = []
    with open(filename, "r", encoding="utf-8") as f:
        for line in f:
            if not line.strip():
                continue
            for token in line.replace(",", " ").split():
                values.append(float(token))

    M1, M2, C1, C2, NN = stats_on_signal(values, N)

    print(f"Число отсчётов NN = {NN}")
    print(f"M1 = {M1}, M2 = {M2}")
    print(f"C1 = {C1}, C2 = {C2}")

    aaa = (C1 * N + C2 * (NN - N)) / (NN - 2)
    t = abs(M1 - M2) / math.sqrt(aaa)

    F = max(C1, C2) / min(C1, C2)

    print(f"t = {t}")
    print(f"F = {F}")

    return values, t, F