Does involving a statistician to help with statistical methods improve the chance that a medical research paper will be published? A study of papers submitted to two medical journals found that 135 of 190 papers that lacked statistical assistance were rejected without even being reviewed in detail. In contrast, 293 of the 514 papers with statistical help were sent back without review (i.e., rejected).

(a) Is this study an experiment or an observational study? Explain.

(b) Arrange these data into a two by two contingency table with the column variable being whether or not statistical help was used.

(c) Compute the percentage of papers not receiving statistical help, that were rejected. Compute the corresponding percentage of papers receiving statistical help, that were rejected. Summarize these results

(d) Is there a significant difference in the proportions of papers with and without statistical help that are rejected without review? Perform a one-sided test. Demonstrate hypotheses, compute the p-value and state your conclusion.

(e) Does your conclusion in part (a) prove that obtaining statistical assistance increases your chance of getting a paper reviewed? Can you suggest another explanation for your conclusion?

(f) What type of hypothesis testing error might you have made in answering part (c)? Give your answer in terms of medical papers and statistical help.

(g) How often are statisticians involved? Show a 95% confidence interval for the proportion of papers submitted to these journals that include help from a statistician. (Chapter 19)

(h) Show an 80% confidence interval for the difference between the proportion of papers rejected without review when a statistician is and is not involved in the research. Interpret your interval.