This document contains Python code that defines functions to calculate statistics about a set of student grades, including the sum and average grade, variance, and standard deviation. The code defines functions to print the grades, calculate the sum and average, variance, and standard deviation. It then calls each function to output the results for a sample grades list.

1. Python programming
Lab 17

29. 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
var = variance / float(len(scores))
return var
def grades_std_deviation(variance):
return variance ** 0.5
variance = grades_variance(grades)
print "All of grades:", print_grades(grades)
print "Sum of grades: ", grades_sum(grades)
print "Average grade: ", grades_average(grades)
print " Variance: ", grades_variance(grades)
print "Standard Deviation: ", grades_std_deviation(variance)