Variables
This term refers to the number of times an experiment is repeated to ensure reliable results.
Repeated Trials
A testable statement that predicts the relationship between the independent and dependent variables.
Hypothesis
There are ___ major classes of information with which an experimental designer must cope.
six
What is [P1] Post-Treatment Behavior or Physical Measurement?
In a typical experiment, the primary focus is on data related to the subject's physical measurements or behavior after treatment. Most experiments gather immediate or short-term results, but more complex studies aim to compare post-treatment behavior across groups that received different treatments or no treatment at all. There are five categories of post-treatment behavior or physical measurements that can be identified.
__________ refers to the property of completely chance events that are not predictable (except in the sense that they are random).
Randomness Randomness ensures that previous events have no influence on future occurrences. In experiments, random assignment of subjects to groups is crucial because it helps eliminate bias and ensures that differences between groups are due to the experimental conditions rather than pre-existing differences. This random distribution creates more reliable and valid results by preventing any group from having an unfair advantage.
These are variables that are held constant throughout an experiment to ensure that they do not interfere with the relationship between the independent and dependent variables.
Controlled Variables
This type of variable is measured or observed in an experiment and changes as a result of the independent variable.
Dependent Variable
A __________ is a written or detailed plan for conducting an experiment, outlining the procedures and methods to be used.
Protocol
What is [P2] Pre-Treatment Behavior or Physical Measurement?
Pre-treatment behavior or condition requires observation, testing, or measurement before the experimental manipulation. Without this data, the design can't address questions about the subjects before treatment. While such information can be gathered from other studies, directly acquiring it increases the cost of the experiment and may introduce confounding effects, where the pre-treatment observation influences the subject's subsequent behavior. Several types of pre-treatment information can be collected.
The __________ variable is the factor that is manipulated or changed in an experiment.
Independent
In the same plant growth experiment, the amount of fertilizer applied would be this type of variable.
Independent variable
This term describes a group in an experiment that does not receive the experimental treatment and is used as a comparison.
Control Group
The __________ is the first step in the scientific method, where you make observations and gather information to develop a question or hypothesis.
Observation
What are[I] Internal Threats to Validity?
This class of information refers to some rival hypothesis that threatens clear interpretation of the experiment. A common group of rivals threatens most experiments, particularly those using human subjects. Typically, the rival hypothesis asserts that something outside of the experiment proper produced the behavior or measurement of interest. To discover whether or not such rival events exert an influence, the designer must usually provide for one or more control groups. Typically, internal threats to validity include:
The ability to repeat an experiment and obtain similar results is known as __________.
Reproducibility
This term refers to the phenomenon where a researcher’s expectations or biases influence the results of an experiment, which can be minimized by controlling variables.
Experimental Bias
The _______________ refers to the behavior of interest being caused by subject being in the center of the experimental stage, e.g., having a great deal of attention focused on them.
Hawthorne Effect This usually manifests itself as a spurt or elevation in performance or physical phenomenon measured. Although the Hawthorne Effect is much more frequently seen in behavioral research, it is also present in medical research when human subjects are present. Dealing with this problem is handled by having a control group that is subject to the same conditions as the treatment groups, then administering a placebo to the control group. The study is termed a blind experiment when the subject does not know whether he or she is receiving the treatment or a placebo. The study is termed double blind when neither the subject nor the person administering the treatment/placebo knows what is being administered knows either.
A __________ occurs when an independent variable is changed at different levels to observe the effect on the dependent variable.
What are [C] Comparable Groups?
Comparability information is used when two or more groups of subjects are involved in an experiment. It ensures that the groups were similar in relevant attributes before and during the treatment, except for the treatment itself. If the designer cannot confirm this comparability, they must acknowledge that differences between groups may have influenced the results. The two main techniques for ensuring comparability are pre-tests or measurements and random assignment. Thus, there are two types of comparability information.
___________ refers to causal inferences drawn "after the fact."
Ex post facto An ex post facto study looks at a causal event that has already occurred, making it a non-experimental study. In such research, researchers compare groups that have been exposed to different conditions, like patients treated with Drug A versus Drug B, and attempt to infer differences in outcomes between the groups. Unlike experimental studies, these studies do not involve controlled manipulation of variables.
This is a type of variable that is not directly part of the experiment but may still influence the outcome. It is often difficult to account for fully.
Extraneous variable
This type of error occurs when an experiment's measurements are inaccurate due to tools or procedures, but could be corrected.
DataYeildBonus; What is [R] Relationship to Treatment?
This information focuses on how treatment effects interact with various factors, such as different types of subjects, other treatments, varying intensities, repeated applications, and treatment sequences. It is typically obtained through blocking, factorial designs, and repeated measures designs.
What are [E] Experiment Errors?
Experiment error refers to some unwanted side effect of the experiment itself which may be producing effect rather than the treatment. The Hawthorne Effect alluded to earlier is a continuing source of experimental error in both behavioral and medical research. Two types of strategies exist to deal with the Hawthorne effect.
A __________ is an outside factor that can affect both the independent and dependent variables, potentially skewing the results.
Confounding