Immediately after the four weeks of treatment, BAT will be administered as posttest to measure the achievement of different group.
3.9 Control of Extraneous Variables
In any quasi-experiment as in this study, some extraneous variables which could introduce bias or errors into the study were handled and taken care of. The following attempts in which the researcher will take care of these extraneous variables is discussed below;
Control of Hawthorne Effect: This happens when student performance are affected because the students are aware that they are being used for an experiment. To prevent this problem, the regular trained biology teachers of the students will be used for both the experimental and control groups. The intention is to reduce students’ suspicion that would have arisen if new teachers had been involved in the experiment....
Since intact classes are sued and intelligence is not measured, there is bound to be error variance in achievement, analysis of covariance (ANCOVA) will be used to control the initial differences across all groups.
Control of Effect of Pretest on Post-test: The period between the protest and posttest will be four weeks. This period is adequate enough to disallow the pretest from affecting the posttest.
Instrumentation Variable: Instrumentation variables are the variables that may be introduced by faulty instrument and this may affect students’ responses. That is, students may misinterpret an item because of its unclear language. To avoid this, trial test was conducted and item analysis carried out, and the shortcomings strengthened before the experiment was carried...
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