def get_DRATS(sum_ptrm_checks, sum_abs_ptrm_checks, x_Arai, end):
    """
    input: sum of ptrm check diffs, sum of absolute value of ptrm check diffs,
        x_Arai set of points, end.
    output: DRATS (uses sum of diffs), DRATS_prime (uses sum of absolute diffs)
    """
    DRATS = (old_div(sum_ptrm_checks, x_Arai[end])) * 100.
    DRATS_prime = (old_div(sum_abs_ptrm_checks, x_Arai[end])) * 100.
    return DRATS, DRATS_prime
input: sum of ptrm check diffs, sum of absolute value of ptrm check diffs,
        x_Arai set of points, end.
    output: DRATS (uses sum of diffs), DRATS_prime (uses sum of absolute diffs)