Table 5.

A proposed progression levels of COV skills tested in this study along with the test version and item, with which the skills are measured.

COV Skill	Test B Spring	Test Version and Item
Deciding if a variable is testable when it is testable (without data)	Low-end	Test A Fishing
Deciding if a set of variables are testable when none is testable (without data)	Low-end	Test A Pendulum
Deciding if an experimental design involving multiple testable and non-testable variables (>2) is a valid COV experiment (without data)	Low-end to Intermediate	Test A Spring
Deciding if a variable is testable when it is not testable (with data)	Low-end to Intermediate	Test B Pendulum
Deciding if a variable is testable when it is testable and influential (with data)	Intermediate	Test B Spring
Deciding if one of several variables is testable when it is testable but non-influential (with data)	Intermediate to High-end	Test B Spring
Deciding if any of several variables are testable when some are influential and some are non-influential (with experimental data)	High-end	Test B Spring