Question

In order to assess whether viewpoints on decriminalization of marijuana for medical purposes change with age, four groups of participants, ages 20, 30, 40, and 50, are asked whether they support this issue. What is one flaw of this design?

Answer 1

There needs to be more criteria than just age. People of all ages smoke so that should have been established beforehand when choosing. More background is needed like culture and income level and race so that one set criteria can be established as deciding factor in opinion difference