I receive this error code: Oops, try again. grades_std_deviation(2.1875) returned 1.0399139475 instead of the expected: 1.4790199458
I am just not sure why my standard deviation calculation is not working correctly. Any suggestions?
grades = [100, 100, 90, 40, 80, 100, 85, 70, 90, 65, 90, 85, 50.5] def print_grades(grades): for grade in grades: print grade def grades_sum(grades): total = 0 for grade in grades: total += grade return total def grades_average(grades): sum_of_grades = grades_sum(grades) average = sum_of_grades / float(len(grades)) return average def grades_variance(scores): average=grades_average(scores) variance=0 for score in scores: variance+=(average-score)**2.0 return variance/len(scores) print grades_variance(grades) def grades_std_deviation(variance): squared=variance**.05 return squared variance=grades_variance(grades) print grades_std_deviation(variance)