Question

Twenty different statistics students are randomly selected. for each of​ them, their body temperature ​( degrees °​c) is measured and their head circumference​ (cm) is measured. if it is found that r=​0, does that indicate that there is no association between these two​ variables?

Answer 1

Yes, it does.

An r-value, or correlation coefficient, goes from -1 to positive 1.  -1 indicates a perfect decreasing match and 1 indicates a perfect increasing match.  0 indicates no relationship between the variables.