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T-Test on Adaption to Physical Environment

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Evolutionary theories often emphases that humans have adapted to their physical environment. One such theory hypothesizes that people should spontaneously follow a 24-hour cycle of sleeping and waking - even if they are not exposed to the usual pattern of sunlight. To test this notion, eight paid volunteers were placed (individually) in a room in which there was no light from the outside and no clocks or other indications of time. They could turn the lights on and off as they wished. After a month in the room, each individual tended to develop a steady cycle. Their cycles at the end of the study were as follows: 25, 27, 25, 23, 24, 25, 26, and 25.

In this problem, you will reach a conclusion about the theory that 24 hours is the natural cycle (that is, does the average cycle lengths under these conditions differ significantly from 24 hours?) Before figuring your response, you must decide what hypothesis test you will use (for example, single sample t-test, dependent samples t-test, independent samples t-test, ANOVA, etc.) Then, using the 5% level of significance, determine the following:

a. The null and research hypothesis

b. The comparison distribution used (for example, a t-distribution of 20 degrees of freedom , a t-distribution of 32 degrees of freedom, etc.)

c. The cutoff score on the comparison distribution (for example, a t-critical or "cutoff t" of 1.5 etc.)

d. Your sample's test score (for example, a t-score of 2.4)

e. Your conclusion on whether to accept or reject the null hypothesis (you must show how the comparison of your cutoff score with your sample's test score leads to your conclusion.)

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Solution Summary

This solution conducts a statistical analysis on the data obtained from the adaption experiment whereby a null and alternative hypothesis is provided, t-critical is determined, and the test statistic is calculated and compared to p-value. A final decision is made to accept or reject the null hypothesis.

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Research methodology related to experimental and quasi-experimental designs

The foundation of both observational research and experimental design methods each contributes significantly to the study and practice of public health.

QUESTIONS
1.What are the strengths and weaknesses of the research methodology presented in Brownson et al. (2007)?
2.What value did using a quasi-experimental design add to the research study?
3.How does this impact the validity of the research project?
4.What do you believe is the best strategy for disseminating research results? Support your position

Reference :
Brownson, R., Ballew, P., Brown, K., Elliott, M., Haire-Joshu, D., Heath, G., et al. (2007). The effect of disseminating evidence-based interventions that promotes physical activity to Health Departments. American Journal of Public Health, 97(10), 1900â?"1907.

This article presents research findings from a study that explored the effects of disseminating evidence-based practices with the goal of promoting physical activity. This article offers a firm example of research reporting in the field of public health.

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