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Does correlation change if variables change?
A correlation value close to 0 indicates no association between the variables. Since the formula for calculating the correlation coefficient standardizes the variables, changes in scale or units of measurement will not affect its value.
How do you find a correlation mean?
Step 1: Find the mean of x, and the mean of y. Step 2: Subtract the mean of x from every x value (call them “a”), and subtract the mean of y from every y value (call them “b”) Step 3: Calculate: ab, a2 and b2 for every value.
What is the correlation between mean and standard deviation?
The correlation is a particular measure of how they vary “together”. Information like mean and standard deviation is how they each behave on their own, without any consideration of other variables. (Specifically, correlation is a property of their joint distribution, while the quantities you mention are properties…
What can one say about the standard deviation for Y?
To say that the standard deviation for Y is zero is the same as saying that the vector Y-mean (Y) is zero (or, more rigorously, that it represents zero in the appropriate vector space). So the question becomes “What can one say about the (cosine of the) angle between the zero vector and the vector X-mean (X)?”.
Is it possible to compute correlation between two variables from just means?
It’s not possible to compute correlation with just information about the individual variables. The correlation is a particular measure of how they vary “together”. Information like mean and standard deviation is how they each behave on their own, without any consideration of other variables.
Which is the best definition of a correlation?
Correlation is a measure of how large/small values in one variable correspond to large/small values in another variable – if one of the variables is equal to a constant with probability 1 (a consequence of having standard deviation 0), then it can’t possibly give information about whether the other variable is small or large.