
No Correlation (does this meme make sense)
A plot can have a Pearson correlation of zero (r=0) but still have a strong non-linear relationship (like a parabola, circle, or U-shape) does labeling a scatter plot "No Correlation" automatically rule out every mathematical relationship, or just linear ones? and got to know from a friend (who studies maths) that to state it is correlated it should be linear, is it correct?