KP290 Lecture Notes - Lecture 16: Selection Bias, Internal Validity, Statistical Model
16 Mar 2017
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Document Summary
Experimental research: control trials and internal validity: choose an appropriate research design - experimental designs, experimental research , attempts to establish cause-and-effect relationships. Var. is manipulated to judge its effect on a dep. Is it ethical to deny treatment to participants: no, can receive standard care , example, control= chemo treatment, experimental = chemo and new drug, main concern of experimental research. And dep. variable valid: back to validity, remember: **both internal & external validity are important in experiments. However, they are frequently at odds in research planning & design. Internal validity - establishing cause and effect: 9 threats to internal validity, threats to i. v. are any other explanations that could have caused the change in the dep. Var. other than the ind. var: history, some unintended event occurred during the treatment period, e. g. , effects of a semester of pe on physical fitness of 5th graders , what if 60% play soccer during the semester, maturation.
