Several neurosurgeons wanted to determine whether a dynamic system (Z-plate) reduced operative time relative to a static system (ALPS plate). The operative times, in minutes, for 14 dynamic replications of the operataion and 6 static replications were obtained and are given below: Dynamic: 370, 360,510, 445,295,315, 490, 345, 450, 505, 335, 280, 325, 500
Static: 430, 445, 455, 455,490, 535
(a) Graph the data as you see fit. Why did you choose the graph(s) you did and what does it (do they) tell you? Also calculate summary statistics relevant to the research question.
(b) Perform a two population t test for means at the 5% level not assuming equal variance and justify why the assumptions of the test are resonably met (or describe what assumptions we are assuming are met). As part of this test, specify your hypotheses, calculate a p value and make a conclusion in the context of the question. Compute the p value just using your calculator and t table. Then find an exact p value by running the same test in R
(c) Construct and interpret an 95% confidence interval for the true difference in means (by hand and then again in R) applying the same assumptions as in part b. Describe how this confidence interval relates to your findings in part b.