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What are the 5 common types of sampling?
What is:
What is reliability?
What is it means the way you test you get the same results
Describe instrumentation as a threat to validity and provide an example
What is any changes that occur from measuring the dependent variable.
Instrument used to measure participants performance may change over time (observers may become bored or tired)
They way that you measure something changes over time
What is the difference between a high degree of internal validity and a low degree of internal validity?
If a study shows a high degree of internal validity then we can conclude we have strong evidence of causality (REJECT THE NULL). Note: The Goal is to always Reject the Null Hypothesis.
If a study has low internal validity, then we must conclude we have little or no evidence of causality (RETAIN THE NULL)
What is validity?
What is you must test what you say you are going to test
Name two characteristics of stratified sampling.
Divides the population into groups called strata. However, this time it is by some characteristic, not geographically. For instance, the population might be separated into males and females.
A sample is taken from each of these strata using either random, systematic, or convenience sampling
Name two characteristics of random sampling
What is:
Each element in the population has an equal chance of occurring.
While this is the preferred way of sampling, it is often difficult to do.
It requires that a complete list of every element in the population be obtained
Computer generated lists are often used with random sampling.
What are the main characteristics of reliability?
What is consistency or dependability
Name 2 characteristics of Systemic Sampling.
Is easier to do than random sampling. In systematic sampling, the list of elements is "counted off".
That is, every kth element is taken.
This is similar to lining everyone up and numbering off "1,2,3,4; 1,2,3,4; etc".
When done numbering, all people numbered 4 would be used
Name two characteristics of Cluster Sampling
Cluster sampling is accomplished by dividing the population into groups --usually geographically. These groups are called clusters or blocks.
The clusters are randomly selected, and each element in the selected clusters are used.
What are the main characteristics of validity?
What is an indication of how sound your research is.
More specifically, validity applies to both the design and the methods of your research.
Validity in data collection means that your findings truly represent the phenomenon you are claiming to measure. Valid claims are solid claims
What is objectivity?
What is testing without bias (noting threats to validity). You must ALWAYS be an OBJECTIVE RESEARCHER and must note any threats to your study.
Name two characteristics of convenience sampling
Convenience sampling is very easy to do, but it's probably the worst technique to use.
In convenience sampling, readily available data is used. That is, the first people the surveyor runs into.
What threat to validity deals with any of the many conditions internal to the participant that change as time passes. Give an example.
What is maturation?
Participants naturally change over time
How is Statistical regression a threat to validity? Provide an example
What is any change due to the tendency for very high or low scores to move towards the mean when re-tested.
Participants sometimes perform very well or very poorly on a measure because of chance factors (e.g.luck).One score isn’t necessarily reliable.
First test, everyone scores high the second and third test eventually going towards the mean
What threat to validity is described as when participants are lost from the study (attrition), the group equivalence formed at the start of the study may be destroyed.
Subject attrition
What threat to validity deals with any of the many events other than the independent variable that occur between a pre-and post-measurement of the dependent variable. Give an example.
What is history?
When an event occurs at the same time as the treatment and changes participants behavior
An event that effect everyone
What is the difference between internal and external validity
Internal validity measures how well a study's results can prove a cause-and-effect relationship within the study's specific conditions, while external validity measures whether those results can be generalized to other people, settings, and times.
What threat to validity is described as any change due to participant loss from comparison groups.
Maturation
What threat to validity is described as any change in performance due to the participants motives or attitudes. Give an example
What is participant bias?
What is experimenter bias? Give an example
What is any change in the participant’s performance that can be attributed to the experimenter.
What threat to validity is described as participants in the experimental and control groups have different characteristics that affect the dependent variable differently. Give an example
What is Differential selection of participants.
What is the difference between mortality and subject attrition. Give an example.
Mortality is a natural occurance often associated with death, while attrition is the dropout of participants from a study.
What threat is described as any change due to the selection procedure used in placing participants in various groups. Selection may often interact with other threats. Give an example
What is Selection?
What is Selection-maturation interaction?
What is the participants selected into treatment groups have different maturation rates. Selection interactions also occur with history and instrumentation.