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Chapter Seven: The Basics of Experimentation II: Final Considerations, Unanticipated Influences, and Cross-Cultural Issues. Participants. Types of participants. Participants. Types of participants Three guidelines to help you choose participants for your research project:. Participants.
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Chapter Seven:The Basics of Experimentation II:Final Considerations, Unanticipated Influences, and Cross-Cultural Issues
Participants • Types of participants
Participants • Types of participants • Three guidelines to help you choose participants for your research project:
Participants • Types of participants • Three guidelines to help you choose participants for your research project: • Precedent
Participants • Types of participants • Three guidelines to help you choose participants for your research project: • Precedent • Availability
Participants • Types of participants • Three guidelines to help you choose participants for your research project: • Precedent • Availability • Nature of the Problem
Types of participants • Precedent • An established pattern
Types of participants • Precedent • An established pattern • If your literature review indicated that a particular type of participant has been used successfully in prior research projects in your area of interest, they you may want to consider using this type of participant.
Types of participants • Availability
Types of participants • Availability • Availability refers to using an easily accessible population from which to draw participants.
Types of participants • Type of Research Project
Types of participants • Type of Research Project • Often the type of research project will determine the type of participant you decide to use.
Number of Participants • Once you have decided what type of participant to use in your research project, you must then determine how many participants you are going to test.
Number of Participants • Once you have decided what type of participant to use in your research project, you must then determine how many participants you are going to test. • In making this decision, there are numerous factors that you must take into account:
Number of Participants • Once you have decided what type of participant to use in your research project, you must then determine how many participants you are going to test. • In making this decision, there are numerous factors that you must take into account: • Finances
Number of Participants • In making this decision, there are numerous factors that you must take into account: • Finances
Number of Participants • In making this decision, there are numerous factors that you must take into account: • Finances • Time
Number of Participants • In making this decision, there are numerous factors that you must take into account: • Finances • Time • Availability
Number of Participants • Finances
Number of Participants • Finances • How much will it cost to test each participant?
Number of Participants • Finances • How much will it cost to test each participant? • Animals need to be purchased and cared for.
Number of Participants • Finances • How much will it cost to test each participant? • Animals need to be purchased and cared for. • It may be necessary to pay humans for their participation.
Number of Participants • Finances • How much will it cost to test each participant? • Animals need to be purchased and cared for. • It may be necessary to pay humans for their participation. • Does the person who actually conducts the experiment need to be paid?
Number of Participants • Time
Number of Participants • Time • As you test additional participants, time requirements will increase, especially if you test participants individually.
Number of Participants • Availability
Number of Participants • Availability • The sheer number of participants that are available may influence how many you choose in your experiment.
Number of Participants • Availability • The sheer number of participants that are available may influence how many you choose in your experiment. • The less within-group variability (i.e., the more homogeneous the participants), the fewer participants we will need.
Number of Participants • Availability • The sheer number of participants that are available may influence how many you choose in your experiment. • The less within-group variability (i.e., the more homogeneous the participants), the fewer participants we will need. • The greater the within-group variability (i.e., the more heterogeneous the participants), the greater the number of participants we will need.
Number of Participants • Power
Number of Participants • Power • The number of participants tested is related to the power of our statistical test.
Number of Participants • Power • The number of participants tested is related to the power of our statistical test. • Power is the probability that a statistical test will be significant (i.e., the experimental hypothesis is accepted when it is true).
Apparatus • IV presentation
Apparatus • IV presentation • Often the nature of the IV will influence the type of apparatus one chooses to use.
Apparatus • IV presentation • DV recording
Apparatus • IV presentation • DV recording • How the DV will be recorded:
Apparatus • IV presentation • DV recording • How the DV will be recorded: • Use of a prepared data sheet in a naturalistic observation study
Apparatus • IV presentation • DV recording • How the DV will be recorded: • Use of a prepared data sheet in a naturalistic observation study • Use of video recording equipment when its presence will not cause reactivity effects.
The Experimenter as an Extraneous Variable • Experimenter Characteristics
Experimenter Characteristics • Physiological
Experimenter Characteristics • Physiological • Characteristics such as age, sex, and race can have an influence on participants’ responses.
Experimenter Characteristics • Physiological • Characteristics such as age, sex, and race can have an influence on participants’ responses. • Psychological
Experimenter Characteristics • Physiological • Characteristics such as age, sex, and race can have an influence on participants’ responses. • Psychological • Characteristics such as hostility, anxiety, introversion or extraversion can also have an influence on participants’ responses.
Experimenter Expectancies • Experimenter expectancies are expectations that cause him/her to behave toward participants in such a manner that the expected response is, indeed, more likely shown.
Experimenter Expectancies • Rosenthal effect
Experimenter Expectancies • Rosenthal effect • The experimenter’s preconceived idea of appropriate responding influences the treatment of participants and their behavior.
Experimenter Expectancies • Rosenthal effect • The experimenter’s preconceived idea of appropriate responding influences the treatment of participants and their behavior. • The results of experimenter expectations are often called Rosenthal effects because Rosenthal and his colleagues were among the first to systematically study them.
Controlling Experimenter Effects • Physiological and Psychological Effects
Controlling Experimenter Effects • Physiological and Psychological Effects • At present the most common procedures for controlling general experimenter characteristics are to:
Controlling Experimenter Effects • Physiological and Psychological Effects • At present the most common procedures for controlling general experimenter characteristics are to: • Use standardized methods