In order to find out is the events are independent, we can check the following formula:
[tex]P(A\cap B)=P(A)\cdot P(B)[/tex]Where A is the event "the teacher is wearing a scarf" and B is the event "there will be a quiz", and P(A⋂B) is the probability of both events together.
If the result from the formula is true, the events are independent.
So using P(A) = 10%, P(B) = 15% and P(A⋂B) = 5%, we have:
[tex]\begin{gathered} 0.05=0.1\cdot0.15 \\ 0.05=0.015\text{ (F)} \end{gathered}[/tex]The result is false, that means the events are NOT independent (that is, they are dependent).