Experimental Method

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.

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

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

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 independent variable?

• The Song
• The Reed
• The Applause

A recent study showed that tea drinkers have lower stress levels than coffee drinkers. Tea drinkers are known to have a higher proportion of yoga practitioners than coffee drinkers, and they exercise on average two hours per week more than their coffee-drinking counterparts. What is the term used to describe these additional factors that might have an effect on the stress levels of tea drinkers?

• cause and effect variables
• confounding variables
• sampling variables
• unfounded variables

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

In a study of effects of alcohol on driving ability, the control group should be given

• a high dosage of alcohol
• one-half the dosage given the experimental group
• a driving test before and after drinking alcohol
• no alcohol at all

A test is set up to test which brand of soda creates the biggest foam explosion when adding a Mentos candy.  Three different sodas were tested. They measured the height of the foam eruption.   What is the dependent variable?

• Brand of soda
• Number of mentos candies used
• Height of foam eruption
• Temperature of soda

Johnny is part of a study designed to test the ability of a pill to cure the migraines of people who experience chronic migraines. After a few days, Johnny finds that the pill has alleviated his migraines and he experiences far fewer than usual. However, unbeknownst to Johnny, the pill he has been taking is nothing more than a sugar pill. What effect is Johnny most likely under the influence of?

• The Stratified Effect
• The Self-Bias Effect
• The Placebo Effect
• The Psychoanalytic Effect