Atwo-way frequency table shows baldness in men over 45 and men under 45:

under 4 over 45 total
bald 24 16 40
not bald 36 24 60
total 60 40 100

based on this data, are baldness and being over 45 independent events?
no, p(bald ∩ over 45) ≠ p(bald) ⋅ p(over 45)
no, p(bald ∩ over 45) = p(bald) ⋅ p(over 45)
yes, p(bald ∩ over 45) ≠ p(bald) ⋅ p(over 45)
yes, p(bald ∩ over 45) = p(bald) ⋅ p(over 45)

it's not a.