I have been assessing some of the relationships between EDTA extractable Pb Vs Pb in plants etc using regression analysis in minitab. I just found a study that did a correlation analysis instead providing the correlation coefficient and p-value in order to assess if the relationship is significant or not.

I tried this my self using minitab - Basic stats - Correaltion - Spearman (non-para) and I found that the relationships with a relatively strong R2-value in my regression analysis was different from what the correaltion analysis found to be significant.

Can someone explain this to me?`

Regards