Stat 100

[BarTopDancer]

The D is passing.

My old roommates gf used to say "C your way to your degree". Then again she was a 4.+ PhD student.

So I think I understand...

Researchers asked a sample of 50 1st grade teachers and a sample of 50 12th grade teachers how much of their own money they spent on school supplies in the previous school year. They wanted to see if teachers at one grade level spend more than teachers at the other grade level.

a. What type of study is found—observational or randomized experiment? Explain. – This study is an observational experiment. The subjects are the teachers, and the amount of personal money they spend on school supplies is being observed.
b. What is the experimental unit? – The experimental unit is the teachers
c. What is the response variable? – The response variable is the money spent
d. What is the explanatory variable? – The explanatory variable is the teachers from different grade levels.
e. Do we have to worry about confounding variables in this instance? Why? If so identify a possible confounding variable? Yes, we have to worry about confounding variables in this example. Confounding variables are found in observational experiments. The confounding variable may be the amount of discretionary money each teacher has to spend.
f. Are either of the terms retrospective study or prospective study relevant? Explain. This study would be a retrospective study – the teachers are asked to recall how much of their own money they spent in the previous school year.