A teacher is experimenting with computer-based instruction. In which situation could the teacher use a hypothesis test for a difference in two population means?

Find x & pleassse me !

International calls require the use of a country code. many country codes a 3-digit numbers. country codes do not begin with a 0 or 1. there are no restrictions on the second and third digits. how many different 3-digit country codes are possible?

Ann and betty together have $60 ann has $9 more than twice betty’s amount how much money dose each have