A study is designed to determine whether grades in a statistics course could be improved by offering special review material.The 250 students enrolled in a large introductory statistics class are also enrolled in one of 20 lab sections.The 20 lab sections are randomly divided into two groups of 10 lab sections each.The students in the first set of 10 lab sections are given extra review material during the last 15 minutes of each weekly lab session.The students in the remaining 10 lab sections receive the regular lesson material,without the extra review material.The grades of the students who reviewed weekly were higher,on average,than the students who did not review every week.What type of study is this?
A)An observational study that is a sample survey
B)An observational study that is not a sample survey
C)An experiment but not a double-blind experiment
D)A double-blind experiment
E)A matched pairs experiment

Question

Quizplus · Accepted Answer

This is an experiment as the researchers are manipulating one variable (offering extra review material) to observe its effect on another variable (grades in statistics course). However, it is not a double-blind experiment as both the students and lab instructors are aware of whether they are receiving the extra review material or not.

A Study Is Designed to Determine Whether Grades in a Statistics