Help with correlation coefficient

[mattjb84]

Trying to calculate the correlation coefficient between the two lists, so far no luck. Any suggestions or help would be greatly appreciated?

from table_utils import *
from stats_utils import *

cars = [29.9, 30.2, 30.3, 30.1, 30.3, 30.4, 30.5, 30.9, 31.1, 31.5, 31.7]
papers = [337, 322, 311, 299, 264, 242, 213, 191, 190, 174, 164]

car_list = []
papers_list = []

for car_row in cars:
    area = car_row[0]
    for papers_row in papers:
        if area == papers_row[1]: 
             car_list.append(float(car_row[1]))
             papers.append(float(papers_row[2])) 

corr = round(corr_coef(car_list, papers_list), 2)
print('Correlation coefficient =', corr)

[j.crater]

What is the problem you are facing... Do you get an error? Is the result wrong?

[ichabod801]

I assume you're getting an error on line 11. I don't understand what you are trying to do with car_list and papers_list. Why not just run corr_coef on cars and papers?

[gontajones]

Maybe this can help you:
Finding-correlation-coefficient-from-2-lists

With this solution the Correlation Coefficient is -0.9068908297699143.

[mattjb84]

Sorry this is my first time working with correlation in python. Was just working with the example I had. Errors I kept getting where;

Traceback (most recent call last):
File "C:\Users\User\Desktop\q6b.py", line 4, in <module>
from table_utils import *
ModuleNotFoundError: No module named 'table_utils'

Line 11 error would have shown up in syntax. But guess its good practice to proof read my code before posting. Was thinking I had to write my own functions as the imports failed?

I'll try using example in the link provided, thanks

[gontajones]

These imports in your codes are not being used. You can just remove them.

The link that I suggested implements the solution like this:

def mean(someList):
    total = 0
    for a in someList:
        total += float(a)
    mean = total / len(someList)
    return mean


def standDev(someList):
    listMean = mean(someList)
    dev = 0.0
    for i in range(len(someList)):
        dev += (someList[i] - listMean)**2
    dev = dev**(1 / 2.0)
    return dev


def correlCo(someList1, someList2):

    # First establish the means and standard deviations for both lists.
    xMean = mean(someList1)
    yMean = mean(someList2)
    xStandDev = standDev(someList1)
    yStandDev = standDev(someList2)
    # r numerator
    rNum = 0.0
    for i in range(len(someList1)):
        rNum += (someList1[i] - xMean) * (someList2[i] - yMean)

    # r denominator
    rDen = xStandDev * yStandDev

    r = rNum / rDen
    return r


cars = [29.9, 30.2, 30.3, 30.1, 30.3, 30.4, 30.5, 30.9, 31.1, 31.5, 31.7]
papers = [337, 322, 311, 299, 264, 242, 213, 191, 190, 174, 164]

print(correlCo(cars, papers))

PS: This is not my code, just added your 2 lists.

[ichabod801]

Those are not standard modules, you would have to install them before you could import them. There should be a tutorial about how to do that in the tutorials section of this board. Or you could use the example gontajones showed.

[Larz60+]

what about scipy: https://docs.scipy.org/doc/scipy-0.14.0/...s.pearsonr