Experimental Method Practice

Suppose a researcher wants to study the effect of drug A on subjects’ alertness. He divides 100 subjects into two groups of 50, an experimental group and a control group. He dissolves drug A in saline solution and injects it into all the subjects in the experimental group. He then gives all the control group subjects an injection of only saline solution.
What is the independent variable? 

• drug A
• saline solution 
• the subjects
• the needles

In a study of the effect of a driver training program on driving skill, a possible operationalization of the dependent variable would be...

• driving quality
• number of accidents
• hours spent training
• amount of traffic

In order to increase typing speed, Mrs. Cornell has redesigned its keyboard and provided a chime that is related to typing speed. The company wants to know if its innovations affect typing speed. Identify the independent and dependent variables in this proposed study.

• The dependent variable is the chime; the independent variables are the chime and typing speed.
• The dependent variable is speed of typing; the independent variables are the keyboard design and the chime.
• The dependent variable is keyboard design; the independent variables are the speed of typing and the chime.
• The dependent variable is the number of errors made; the independent variables are the chime and the speed of typing.

To determine the effects of a new drug on memory, one group is given a pill that contains the drug. A second group is given a sugar pill that does not contain the drug. This second group constitutes the

• random sample
• experimental group
• control group
• test group

What would be considered the independent variable in the following hypothesis: "Students assigned to use their laptops each day in study hall will have lower average grades at the end of the semester than students banned from using their laptops."

• The presence or absence of laptops
• The number of students in the study hall
• The end of semester grades for the participants
• All of the above would be considered independent variables

A researcher wants to conduct an experiment to determine if eating a cookie before class each day improves student grades.  He uses two psychology classes for the experiment, providing daily cookies to one and nothing to the other.  At the end of the semester, the researcher compares the final grades of students in the two classes. What is the independent variable for this experiment

• The students in the class that received the cookies
• The presence or absence of the cookies
• The students in the class that didn't receive cookies
• the period of the day that the two classes met

Dr. Schulte wants to investigate if aggressive behavior in children is increased if they view violent videos.  In this instance, the dependent variable is

• 
  violent videos
• 
  aggressive behavior
• 
  a placebo
• 
  the control condition

An experiment is performed to see if background music improves learning.  Two groups study the same material, one while listening to music and another without music. The independent variable is

• learning
• size of group
• material studied
• presence of music

Squidward found new reeds to tryout for his clarinet.  He used an APPLAUSOMETER to measure applause after playing  Under the Sea with each reed.  The results were put in the table.
What was the dependent variable?

• The Song
• The Reed
• The Applause

Maria wants to know if birds prefer to eat in one place over another. She makes three feeders out of 2-liter bottles and paints all of them red. She fills each of the feeders with the same amount of mixed birdseed, and plans to keep the feeders out for 10 days before measuring how much seed is eaten from each feeder. She puts each of the feeders in her back yard: one feeder in a large dead tree, another feeder she sits on the dog house, and the last she sits in a small bushy tree.
What is the dependent variable?

• Length of the birdfeeders
• Amount of time feeders are outside
• Amount of seed eaten
• Location the feeders are put in.