One-Way Experimental Designs - Essay Example

Applied Assignment: One Way Experimental designs When researchers of a particular study were interested in the effectiveness of a particular treatment for insomnia, they decided to investigate the possible effects of psychological state on insomnia. In this case, fifty insomnia sufferers who responded to a newspaper advertisement were contacted, and each was given a pill with instructions to take it before going to sleep that night. The pill actually contained milk powder (a placebo). The participants were then randomly assigned to receive one of two sets of instructions about the pill.

One half of the participants were told that the pill will make them feel "sleepy," and the other half are told that the pill will make them feel "awake and alert." The next day the participants returned to the lab and were asked to indicate how long it took them to fall asleep after taking the pill. The individuals who were told that the pill would make them feel sleepy reported that they fell asleep faster than the participants who were told the pill would make them feel alert. In this experiment, the Independent Variable was the ‘Set of Instructions’ given to the participants about the pill they were asked to ingest.

This Independent variable had two levels. The first level was the set of instructions stating that the pill would make the participant feel ‘sleepy’; while the second was the set of instructions that state that the pill would make the participant feel ‘alert and awake’. Thus, two groups were formed, each given different instructions about the same pill. The attempt here was to see if the instructions themselves (by virtue of their difference) cause any change in sleeping activity.The dependent variable of this study is the ‘duration of time required by the subject to fall asleep’.

This was measured as the time taken as reported by the participants themselves. The study used a between participants research design. This is evident from the fact that the description states that the participants were randomly divided into two groups; each group receiving one of the two treatments (levels of the I.V.). Thus, the two levels of the study were exposed to different persons; and no person experienced both levels. This shows that this was a between participants designAlthough we have no access to the actual statistical analyses conducted by the researchers; If the ANOVA F value were to be significant for this study; it would mean that there was a significant difference in the mean values (of the time taken to fall asleep) of the two groups.

Given a significant difference between the two groups’ time taken to fall asleep; the next logical step would be to consider the difference of this difference. The research hypothesis would require the difference to be such that the group who were told that they would feel sleepy should have taken less time to fall asleep by the power of suggestion; while the group that was told that they would be alert and awake would report far more time required to fall asleep. As indicated in the description then, the mean for the group that was told that the pill would make them ‘sleepy’ would have to be significantly lower than the mean for the group that was told that the pill would make them ‘alert and awake’ for the hypothesis to be verified.

From this, we can conclude that with the subjects tested, if those who were primed to expect sleeping soon did actually sleep sooner than those who were primed to expect that they would sleep late, the groups did experience differing experiences. The significant F value would imply that the chances of this occurring by chance in the population would be less than 5 %; and so, it may be accepted that the instructions did affect the time required to fall asleep.References:Stangor, C. (2010). Experimental research: One way designs.

Research Methods for the Behavioral Sciences (4th ed.). Pp. 183 – 203. Boston, MA: Houghton Mifflin. Snodgrass, J.G, Levy-Berger, G. and Haydon M. (1985). .Human experimental psychology. Oxford university press. New York. USA. Print.