Dunno what am I doing wrong,


#1



https://www.codecademy.com/courses/python-intermediate-en-7mgOa/2/1?curriculum_id=4f89dab3d788890003000096

doesnt do the math correctly


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
    scrs = sum(scores)
    for score in scores:
        variance += (average - score) ** 2
        variance == variance / scrs
    return variance
print grades_variance(grades)


help please :smiley:

OUTPUT : 4342.92307692
None

Error : Oops, try again. grades_variance([7, 0, 2, 9, 7, 4, 8, 8, 2]) returned 85.5555555556 instead of the expected: 9.5061728395


#2

Just change the last function. The grades_variance can be as simple as

def grades_average(grades):
sum_of_grades = grades_sum(grades)
average = sum_of_grades / float(len(grades)) #See it? sum of grades divided by number of grades
return average


#3

Umm somehow I feel like an idiot, I sent wrong exersice.

That's the real last function.

def grades_variance(scores):
average = grades_average(scores)
variance = 0
for x in scores:
variance = variance + (average - x) ** 2
tot_variance = variance / len(scores)
return tot_variance
print grades_variance(grades)


#4

did the same thing except the variable tot_variance and score instead of x..

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
        variance == variance / len(scores)
    return variance
print grades_variance(grades)

#5

Well there is a little difference between them, I don't know why but when you count something it must be a new variable. Strange, isn't it?


#6

oh 2 variables didnt see that


#7

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(grades):
average = grades_average(grades)
variance = 0
for grade in grades:
variance += (average - grade) ** 2
total_var = variance/len(grades)
return total_var
print grades_variance(grades)

def grades_std_deviation(variance):
return variance ** 0.5
variance = grades_variance(grades)
print grades_std_deviation(variance)


#8

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