How can two variables have different means but not be correlated?

A t-test confirmed that two variables had significantly different means, but Spearman said they’re not correlated. One variable is ordinal (strong, weak) and the other is interval (scores). So the strong folks have significantly higher test scores than the weak group, but the "strong" category is not associated with higher test scores? I can wrap my head around these stats. Can someone explain this to me conceptually?

I agree. You are absolutely right. It is a bit confusing my mind also. Let me consult my mentor today evening and let you know tomorrow.