import math


def compute_stats(grade_list):
    """Compute and return the mean and standard deviation of the grades.

    Args:
        grade_list: List[float]. A list of numerical grade values.

    Returns: a Tuple[float] of the mean and standard deviation.
    """
    # Calculate the mean and standard deviation of the grades
    mean = sum(grade_list) / len(grade_list)
    sd = 0  # standard deviation
    sum_of_sqrs = 0
    for grade in grade_list:
        sum_of_sqrs += (grade - mean) ** 2
    sd = math.sqrt(sum_of_sqrs / len(grade_list))
    return mean, sd