What is the difference between pretest and posttest?
Typically, a pretest is given to students at the beginning of a course to determine their initial understanding of the measures stated in the learning objectives, and posttest is conducted just after completion of the course to determine what the students have learned.
Is a control group always necessary?
Yes. In an experiment, you need to include a control group that is identical to the treatment group in every way except that it does not receive the experimental treatment. Without a control group, you can’t know whether it was the treatment or some other variable that caused the outcome of the experiment.
Why does a good experiment include a control group?
The control group consists of elements that present exactly the same characteristics of the experimental group, except for the variable applied to the latter. This group of scientific control enables the experimental study of one variable at a time, and it is an essential part of the scientific method.
What is a posttest-only control group design?
Entry. The posttest-only control group design is a research design in which there are at least two groups, one of which does not receive a treatment or intervention, and data are collected on the outcome measure after the treatment or intervention.
Which type of research design can only be used with 2 groups?
Two-Group Experimental Designs The simplest true experimental designs are two group designs involving one treatment group and one control group, and are ideally suited for testing the effects of a single independent variable that can be manipulated as a treatment.
What are the disadvantages of lab experiments?
- Demand characteristics – participants aware of experiment, may change behaviour.
- Artificial environment – low realism.
- May have low ecological validity – difficult to generalise to other situations.
- Experimenter effects – bias when experimenter’s expectations affect behaviour.
What are the strengths and weaknesses of a laboratory experiment?
1. Lab Experiment
- Strength: It is easier to replicate (i.e. copy) a laboratory experiment.
- Strength: They allow for precise control of extraneous and independent variables.
- Limitation: The artificiality of the setting may produce unnatural behavior that does not reflect real life, i.e. low ecological validity.
What are the advantages and disadvantages of experiments?
Advantages and Disadvantages of Experimental Research: Quick Reference List
|researcher can have control over variables||can produce artificial results|
|humans perform experiments anyway||results may only apply to one situation and may be difficult to replicate|
What are the benefits of working in a laboratory?
Six Benefits to Working in the Lab on the Weekend
- Beat the commute. When I was a post doc, I commuted 60 miles one way to the lab, with the traffic.
- Relaxed atmosphere. I felt a lot less harried working in the lab by myself.
- Have the place to yourself.
- Work more efficiently.
- Concentrate on hard/long experiments.
- Peace of mind.
Which person is in the control group answer?
The control group is composed of participants who do not receive the experimental treatment. When conducting an experiment, these people are randomly assigned to be in this group. They also closely resemble the participants who are in the experimental group or the individuals who receive the treatment.
What is the purpose of a lab experiment?
The purpose of an experiment is to answer a question by testing a hypothesis. During an experiment you may collect a lot of information, or data. But that data is not very useful unless it is organized. The purpose of a lab report is to organize and communicate what you did in your experiment.
What are the benefits of experiments?
Advantages of laboratory experiments:
- Experiments are the only means by which cause and effect can be established.
- It allows for precise control of variables.
- Experiments can be replicated.
When would you use a control group?
- Control group, the standard to which comparisons are made in an experiment.
- A typical use of a control group is in an experiment in which the effect of a treatment is unknown and comparisons between the control group and the experimental group are used to measure the effect of the treatment.
What is the difference between a test group and a control group?
An experimental group is a test sample or the group that receives an experimental procedure. This group is exposed to changes in the independent variable being tested. A control group is a group separated from the rest of the experiment such that the independent variable being tested cannot influence the results.
Which study design does not require a control group?
True experimental designs require random assignment. Control groups do not receive an intervention, and experimental groups receive an intervention. The basic components of a true experiment include a pretest, posttest, control group, and experimental group.
What are the advantages and disadvantages of posttest only design?
When might you use the posttest-only design? The advantage would be that without a pretest you wouldn’t be taking as much time. The disadvantage would be the useful-side of the pretest where you can see changes as well as attrition effects.
What is a control group in statistics?
A control group is a statistically significant portion of participants in an experiment that are shielded from exposure to variables. In a pharmaceutical drug study, for example, the control group receives a placebo, which has no effect on the body.
What is a control group study?
In a scientific study, a control group is used to establish a cause-and-effect relationship by isolating the effect of an independent variable. Then they compare the results of these groups. Using a control group means that any change in the dependent variable can be attributed to the independent variable.