Based on the scale of measurement for the data, which of the following tests are parametric? Which are nonparametric?
(a) A researcher measures the average age that schizophrenia is diagnosed among male and female patients.
(b) A researcher measures the proportion of schizophrenic patients born in each season.
(c) A researcher tests whether frequency of Internet use and social interaction are independent.
(d) A researcher measures the amount of time (in seconds) that a group of teenagers uses the Internet for school-related and non-school-related purposes.