Question

Python Problem:

Problem 1: Computing variance For this problem, you will write a function variance that takes a list whose elements are numbers (floats or ints), and returns their variance, a single number. (If you don't remember how to compute variance, check the lecture notebook; it's one of the intermediate steps in computing standard deviation.) You should not use NumPy or any other Python libraries for this problem. For now, worry only about correctness, not efficiency. Passing an empty list to variance should result in a ZeroDivisionError exception being raised, although you should not have to explicitly raise it yourself. [] def variance (data): ""Takes a list of numbers and returns their variance.""". # YOUR CODE HERE raise NotImplementedError() [] ### Tests for variance assert_almost equal(variance([3, 4, 5, 6]), 1.25) assert_almost_equal(variance ([3, 4, 8]), 4.666666666666667) assert_almost_equal(variance ([0.0, 0.0, 0, 0]), 0) assert_almost_equal(variance([1.5, 2.5]), 0.25) assert_almost_equal(variance([18, 19, 20, 21, 22]), 2.0) assert_almost_equal(variance([0, 43, 1, 1, 55]), 575.2) try: variance([]) except(ZeroDivisionError): pass

Variance Explanation:

Answer 1

Python 3 code

============================================================================================

def variance(data):
mean=sum(data)/len(data)
total=0.0
for i in data:
total+=(i-mean)**2

return total/len(data)

example_data=[18,19,20,21,22]

try:
v=variance(example_data)
print(v)
except(ZeroDivisionError):
pass
  

============================================================================================

Output

variance_1.py - DyChega/python3.6codes/vanance_1.py 36.5) Eile Edit Format Run Options Window Help det variance (data) mean-sum(data)/len (data) total 0.0 tor in data: total-(i-mean) **2 Python 3.65 Shell - X File Edit Shell Debug Options Window Help Python 3.6.5 (v3.6.5:59c0932b4, Mar 28 2018, 17:00:18) [MSC v.1900 64 bit (AMD6 4) ) on win32 Type copyright", "credits" or "license() for more information. return total/len (data) example_data-t18, 19, 20, 21, 22) -- 2.0 - RESTART: D: /Chegg/python3. Ecodes/variance_1.py - y-variance (example_data) print (v) except (ZeroDivisionError): Ln: 6 Col: 4 Type here to search o e o AOC Ln: 18 Col: 0 @ IND 12:41MP 04-02-20202