Which of the following statements about the Pearson's correlation is correct?

1. A Pearson's correlation calculates covariance between two variables measured in the units of the criterion variable

2. Whether a Pearson's correlation is positive or negative depends on whether you assign variable 1 (eg. height) as variable X or as variable Y

3. The scores on variables X and Y or considered as a group, not paired observations. Therefore, you can calculate the sum of the products by pairing any person's scores on variable X with any other person's score on variable Y

4. 1 degree of freedom is removed from the calculation of covariance to reflect the estimation of the true covariance in the population

5. All the above

6. None the above