Among people who have a history of chronic trouble falling asleep, some rely only on sleeping pills to help them fall...

on October 26 at 01:47PM

Why is D correct?

Hello! Could you please explain why D is correct? Thank you!

1 Reply

Michelle on October 27 at 02:14PM

Thanks for your question @Lucie

D is correct because if those who have the most trouble falling asleep are those most likely take sleeping pills, then those in the sleeping pill group, on average, have a harder time sleeping than those in the behavior modification group. This is true before either group begins their respective treatments, so we cannot draw any conclusions from that fact that it remains true after both groups have begun their respective treatments. The two groups are not comparable, so if D is true then we cannot draw any conclusions about one type of treatment relative to the other.