"-the time people spend at work and the number of friends they have" would be "causation"; because the more/less time someone spends at work is implied to be the *cause* of their number of friends.
"-the length of a person's hair and his or her math skills" would be "no relationship" seeing as there's nothing that relates these two variables that could have an affect on the outcome of one or the other.
<span>"-a student's test scores in math and physics" would be "correlation" because the two subjects are similar enough that any outcome in one could very well be similarly related to the outcome in the other. </span>
