EXPERIMENTAL RESEARCH - metolit DOCX

Title	EXPERIMENTAL RESEARCH - metolit
Author	Siska Maldin
Pages	2
File Size	13.4 KB
File Type	DOCX
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EXPERIMENTAL RESEARCH: DEFINITION AND PURPOSE In an experimental study, the researcher manipulates at least one independent variable, controls other relevant variables, and observes the efect on one or more dependent variables. The independent variable, also called the experimental variable, cause or treatment, is that process or activity believed to makee a diference in perfoormance. The dependent variable, also called the criterion variable, efect or postest, is the outcome ofo the study, the measure ofo the change or diference resulting forom manipulation ofo the independent variable. When conducted well, experimental studies produce the soundest evidence concerning hypothesized cause-efect relations. The Experimental Process The steps in an experimental studies include selecting and defning a problem, selecting participants, and measuring instruments, preparing a research plan, executing procedures, analyzing the data, and foormulating conclusions. An experimental study is guided by at least one hypothesis that states an expected causal relation between two variables. In an experimental study, the researcher foorms or selects the groups, decides how to allocate treatments to each group, controls extraneous variables and observes or measures the efect on the groups at the end ofo the study. Manipulation and control Direct manipulation by the researcher ofo at least one independent variable is the characteristic that diferentiates experimental research forom other types ofo research. Control refoers to eforts to remove the infuence ofo any variable, other than the independent variable, that may afect perfoormance on the dependent variable. Two diferent keinds ofo variables need to be controlled: participant variables, on which participants in the diferent groups may difer, and environmental variables, variables in the setng that may cause unwanted diferences between groups. THREATS TO EXPERIMENTAL VALIDITY Any uncontrolled extraneous variables that afect perfoormance on the dependent variable are threats to the validity ofo an experiment. An experiment is valid ifo results obtained are due only to the manipulated independent variable and ifo they are generalizable to situations outside the experimental setng. Internal validity is the degree to which observed diferences on the dependent variable are a direct result ofo manipulation ofo the independent variable, not some other variable. External validity is the degree to which study results are generalizable to groups and environments outside the experimental setng. GROUP EXPERIMENTAL DESIGNS The validity ofo an experiment is a direct founction ofo the degree to which extraneous variables are controlled. Participant variables include organismic variables. Organismic variables are characteristics ofo the subject or organism that cannot be altered but can be controlled foor. Intervening variables intrude between the independent variable and the dependent variable and cannot be directly observed but can be controlled foor....