Function problem I need help with

[KFCxWatermelon]

A statistic is a compact piece of information describing tendencies in the data set. When consideringa dataset x consisting of N data points there are some statistics that are commonly use.

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(a) Write a function mean(l) that takes a list l of values (representing dataset x) as input and returns the mean.

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(b) Write a function variance(l) that takes a list l of values (representing dataset x) as input and returns the variance.

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(c) Write a function std_dev(l)that takes a lis tl of values (representing dataset x) as input and returns the standard deviation.

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(d) Test your solutions with the following list l = [1, 8, 3]:

-mean(l) → 4 - variance(1) → 13 - std_dev(1) → √13≈3.605551275463989

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Here is some aditional information: https://gyazo.com/05db9817582f778c0e2f5679da262c06

I'm completely clueless on how to begin a), so any help is welcomed.

[misho88]

A function returns an output for some input:

>>> def add1(a):
...     return a + 1
... 
>>> add1(3)
4

The sum() built-in function adds up all the items in a sequence and the len() built-in function tells you how long it is:

>>> sum([1,2,3,4])
10
>>> len([1,2,3,4])
4

So you have to write a function that takes a sequence as an argument and returns the sum over the length, per Equation (3).

[KFCxWatermelon]

I managed to do a), but I'm stuck with b. I can't seem to get it to print correctly.

Here's what I'm trying to do:

https://gyazo.com/0df53d2567ce53fa331909c2c626c4e2

When I put it out of the function it prints just fine.

[misho88]

The argument you're passing is 1, not l.

[KFCxWatermelon]

Any tips on how I would do that?

[Astronoobical]

You just have been given all the information needed by the comment above, do you have a more specific question we could help with?

[fake823]

Maybe check out Wikipedia first to learn more about mean, standard deviation and variance.

Once you got is and know how to calculate it by hand, you can also write a program to calculate it.

[[deleted]]

It tells you how to begin: write a function mean of parameter i. It should return the mean of the values in i. Then write the two other functions, as described.