From 2010 to 2015, a group of researchers conducted an experiment using two types of pain medication: pill A and pill B. The researchers gave the doctors the puis
in unidentified packages so they would not know which package was pill A and which package was pill B. The patients participating did not know which pill they
received either. What is this an example of?
A. The effect of a treatment unit
B. The placebo effect
C. A control group study
D. A double-blind study
E. Voluntary response bias

Two groups of students were asked how many hours they spent reading each day. the table below shows the numbers for each group: group a 1 2 1 1 3 3 2 2 3 group b 3 2 3 2 2 2 1 1 2 based on the table, which of the following is true? the interquartile range for group a students is 0.5 less than the interquartile range for group b students. the interquartile range for group a students is equal to the interquartile range for group b students. the interquartile range for group a employees is 0.5 more than to the interquartile range for group b students. the interquartile range for group a employees is 1 more than the interquartile range for group b students.