Classify the following scenarios as one-sided or two-sided tests.
one-sided hypothesis test
test whether incoming students at a business school receive better grades in their classes if they've taken an on-line program covering basic material
test whether there is a difference between men's and women's usage of a mobile fitness app
two-sided hypothesis test
test whether the number of listeners of a streaming music service has changed after they changed the user interface
test whether users of a commercial website are less likely to make a purchase if they are required to set up a user account on the site