You, as an eager young behavioral scientist, have noted that many people don't wash their hands when they are in a public rest room, unless there is someone there who they believe is watching them. Because you are very aware of the public health impact of handwashing, you want to encourage washing of hands in public restrooms.
You design an experiment in which there are two conditions. In one condition, you place a person outside the door of the restroom, and count the number of people who go in and go out. That person also listens for the faucets to come on and go off.
In the second condition, you place a person inside the restroom, looking through his/her bookbag for something. This person records the number of people who come into the restroom, and the number of those people who wash their hands.
After several trials of each condition, you compare the number of people who washed their hands in the first condition to the number of people who washed their hands in the second condition.
You are not surprised to discover that people who went into the restroom where someone was already in there washed their hands more often than those who went in to a restroom by themselves. This confirms your belief that people who are being watched are more likely to wash their hands in public restrooms than those who believe that they are in there alone.
Okay, now answer the following questions, and submit the file to the Digital Dropbox for this course:
1: What do you think the hypothesis was in this experiment?
2: What was your independent variable? What was your dependent variable?
3: Which condition was your control group condition?
4: Is this experiment basic research, or applied research? (Hint: was this experiment intended to help solve a specific problem, or just to expand the breadth of knowledge about behavior?)
5: Do you think that this experiment utilized a heterogeneous (or normally distributed) sample? Why, or why not?
psychology - Ms. Sue, Thursday, August 18, 2011 at 7:32pm
What part of this assignment don't you understand?
psychology - Jkim, Thursday, August 18, 2011 at 7:51pm
I don't understand what is an independent and dependent, control group?? I'm lost
psychology - Ms. Sue, Thursday, August 18, 2011 at 7:56pm
The control group is the one that had no one watching them.
psychology - Jkim, Thursday, August 18, 2011 at 8:01pm
ok so can you give me a hint for the indepedent variable? I want to say people washing their hands is it but I'm not sure if that's right
psychology - Ms. Sue, Thursday, August 18, 2011 at 8:12pm
You've hypothesized that people wash their hands more often when they think someone is watching them.
An independent variable is exactly what it sounds like. It is a variable that stands alone and isn't changed by the other variables you are trying to measure. (from the nces website above)
The independent variable is the group that has no one watching them.
psychology - Jkim, Thursday, August 18, 2011 at 9:59pm
dependent would be, the group that has someone watching them?
control group is that group that isn't affected by anything right?
psychology - PsyDAG, Friday, August 19, 2011 at 11:35am
An independent variable is the potential stimulus or cause, usually directly manipulated by the experimenter, so it could also be called a manipulative variable.
A dependent variable is the response or measure of results.
Extraneous variables — other than the independent variable — potentially can affect the dependent variable, so they must be controlled. If possible, you try to keep them constant between the experimental and control group.
The experimental group receives the independent variable.
The control group is similar to experimental, except it does not receive the independent variable. Extraneous variables are balanced between experimental and control groups.
Types of experiments
1. Single blind gives the control group a placebo — a substance that is inert, it has no physical effect. Subjects don't know if they are in experimental or control group to reduce placebo effect, a change in behavior solely due to believing that you are getting the independent variable.
2. Double blind keeps both subjects and experimenter ignorant of group setup. Distribution of the independent variable and placebo are controlled by third party. This controls for experimenter bias and self-fulfilling prophecy, which means that experimenters with particular expectations are likely to consciously or unconsciously to bias the experiment and influence it to conform to their expectations.
As an example, suppose you want to find out if fluorides reduce dental cavities. You would find two groups, trying to control the extraneous variables. Extraneous variables are found by surveying previous research in the area. In this case, you would match the groups in terms of previous history of cavities, diet and dental hygiene habits including how and how often they brush their teeth.
The experimental group would get toothpaste with the independent variable, the fluoride, while the control group would not have the fluoride in their toothpaste. The toothpaste without the fluoride would be the placebo.
The dependent variable would be the number of cavities after participating in the experiment for a time. The dependent variable indicates the results, but it is not the results. At the end of the experiment, both groups could have no change in cavities or one of the groups could have a greater reduction in cavities. (Of course, if the fluoride increased cavities, you wouldn't want to use it.) All of these varied results would be indicated in terms of the dependent variable.
If only the subjects do not know who is getting the fluoride, it is a single blind experiment. If both the subjects and experimenter do not know, it is a double blind.