Discuss QuasiExperimental Designs

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Multiple-baseline design differs from a reversal design in that the multiple-baseline design measures multiple variables prior to and after a treatment while a reversal design (also known as ABAB design) is a kind of single-case experimental design which can only measure a single case. Additionally, in Multiple-baseline design, treatment is often introduced to a multiple number of people at different intervals.Quasi-experiments have a number of advantages as well as potential weaknesses. Some of the major advantages of quasi-experiments include greater validity (as it involves more real world conditions) and significantly much more feasibility given logistical and time constraints (Trochim and Donnelly, 2008). On the other hand, the weaknesses of quasi experiments include less controlled variables, and lack of randomness. The absence of randomization is a fundamental weakness as it can lead to weaker evidence by making. This weakness does not always matter as long as it is recognized as quasi- experiment offers a powerful research tool especially in areas where true experiments may not be feasible.Yes, when participants are randomly assigned to groups, it is assumed that the groups are equivalent at the beginning of the study. This is particularly attributed to the randomness of the selection. However, the participants eventually became nonequivalent at the end due to the researcher’s lack of control over the selected participants for ach group. This may be solved by using pretests and covariance experimental designs.The particular outcomes of a given study can be used to effectively suggest that a threat is likely to have been present include covariation, temporal precedence as well as the presence of other plausible alternative explanation for the research results may reveal a threat to the validity of the research.a. Non-equivalent control group pretest only: Involves comparing the treatment and comparison