One of the most common measures in statistics is the z-score. What it measures is how many standard deviations away from the mean a data point is.

First, let’s check out how far each point in our y data set is away from the mean.

xVals = list(range(100))
yVals = [x+randint(-20,20) for x in xVals]
xVals = np.array(xVals)
yVals = np.array(yVals)
print(yVals-yVals.mean())

Now, if we divide everything by the standard deviation…

print((yVals-yVals.mean())/yVals.std())

Now I want to introduce the correlation equation, there will be two versions, a standard one and a one using z-scores.