public override Statistics GetStatistics()
        {
            var result = new Statistics();

            result.CalculateStatistics(grades);
            return(result);
        }
        public override Statistics GetStatistics()
        {
            var result = new Statistics();

            using (var reader = File.OpenText($"{Name}.txt"))
            {
                var line = reader.ReadLine();
                while (line != null)
                {
                    var grade = Convert.ToDouble(line);
                    grades.Add(grade);
                }
            }

            result.CalculateStatistics(grades);
            return(result);
        }