Introduction To Biostatistics Assignment 3

Please find assignment in this file.it is question-answer format.

Students will be presented with a research question, a related published journal article and an appropriate data set. Students will be asked to critically appraise selected statistical aspects of the article provided.  Then, using the R Commander and the data set provided, students will be asked to conduct and report their own analyses addressing the research question. A Word template will be provided for the answers.

Criteria

You will be assessed on the following:

• The accuracy, depth and relevance of your critical appraisal
• The appropriateness of your choice of statistical methods in relation to the research question and data set.
• The accuracy, clarity and completeness of your description of the statistical methods used.
• The accuracy, clarity and completeness of your presentation of the results of the statistical analyses.
• The accuracy, depth and relevance of your interpretation of results and your answer to the research question.

Please avoid pasting screenshots of R Commander output into your assignment (graphs are fine). Raw output does not identify the answer to the question. Where ever possible present your answer as a sentence or paragraph.

You must type your answer in the given answer template only. only that file will be accepted for submission.

Provide your appraisal of the strengths and weaknesses of the presentation of the statistical material in Winkleby et al, 1992 (300-400 words, 18 marks)

Strengths: In my opinion, the primary strength of Winkleby et al's description of statistical material is that it is completely to the point and at the same time quite comprehensive. The details about the samples are well presented with having important information like the span of the age of the population considered.  

Secondly, the rationale behind pooling the data from four different cross-sectional studies is clearly described. Also, what was done with the unemployed samples is well stated. As non-responded questionnaire is quite commonly encountered in these kinds of studies, the assumption to handle those cases is adequately described.

Thirdly, all the independent explanatory variable are separately described to ensure that the choice of analytical framework gets justified. The coding method for the dependent variable is also discussed to substantiate the analysis.    

Weaknesses: Along with these strengths, I found quite a few weaknesses of this potion which should have been taken care of. 

First of all, the total number of participants in each of the cross-sectional study was not mentioned. Furthermore, the absolute number of dropped unemployed participants in various categories are given, their percentage in the total number of participants, however, is not clearly mentioned. If this percentage was found to be significant, then alternatives to dropping those participants should have been considered. Moreover, the gender distribution of those dropped participants is not at all highlighted. 

Secondly, how partially completed questionnaires are dealt is not described. Generally, entries with 'NA' can affect the regression substantially, hence the mechanism to handle those entries should have been described sufficiently. 

Thirdly, in my opinion, the description of the analytical methods is not adequate. The different types of regression models used in the study are not discussed in detail. The basic equation for those models also should have been discussed in the method section of the paper. Moreover, the rationale behind choosing those methods also be stated clearly in this section. Even, the software used for conducting the statistical analysis is also not mentioned. 

Fourthly, 'homemaker' category is dropped in the multivariate analysis which actually will add up to 1/3 of women population. The justification for dropping that category is not provided, and any other alternative is also not considered.  

Finally, it is not mentioned whether in the study (both in the data collection process as well as in the analysis) any ethical code and conducts were confirmed or not.