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Page 1 of 3 STAT221A – Statistical Data Analysis Assignment 3 Due 05/05/03 STAT221A – Statistical Data Analysis Assignment 3 Handed out: Friday, April 11th, 2003 Due: Monday, May 5th, 2003 REMINDER: Terms test Wednesday, April 30th 2003, During Lecture, OPEN BOOK The aim of this assignment is to familiarise yourself with using R for hypothesis testing. Make sure you read the questions thoroughly and that all work is your own. Suspected cheating will result in a zero for the assignment or worse! Present your answers to each question as a report. You do not need to include your R-code, but include output as necessary with an explanation. If you draw a plot, please explain why you have drawn it and what you can see (if anything) in the plot. If you present summary statistics (and you should) for any data set, put them in a nice easy to read table and summarise the results referring to the table. Question 1 [15 marks] A person’s blood clotting ability is typically expressed in terms of a ‘prothrombin time’, which is defined to be the interval between the initiation of a prothrombin-thrombin reaction and the formation of the final clot. Factors affecting the length of a person’s prothrombin time have profound medical significance. A study was undertaken to determine what effect, if any, aspirin has on this particular function. Twelve adult males participated. Their prothrombin times were measured before and three hours after each was given two aspirin. tablets (650mg) and are given below (Yochem and Roach, 1971): Subjec t Before Aspirin After Aspirin 1 12.3 12.0 2 12.0 12.3 3 12.0 12.5 4 13.0 12.0 5 13.0 13.0 6 12.5 12.5 7 11.3 10.3 8 11.5 11.3 9 11.5 11.5 10 11.0 11.5 11 11.0 11.0 12 11.3 11.5 Does aspirin reduce prothrombin times? Your answer should include: 1. Some summary statistics for the data 2. A relevant plot 3. A hypothesis test (make sure to state your hypotheses) 4. Any assumptions you have to make and some indication of their validity 5. A confidence…