Lab Assignment 04: Motorcycle Helmet Law In 2012, the state of Michigan repealed its' universal motorcycle helmet laws. With this change in legislation, only drivers under the age of 21 were required to use protective headwear. To study the potential eff ects of repealing the helmet law, the Michigan State Police Offi ce of Highway State Planning sponsored a study carried out by researchers at the University of Michigan. The researchers examined motorcycle crash and fatality data for roughly two years after the repeal of the helmet law 1 . Of the 7,084 motorcyclists reported to be involved in accidents after the repeal, the fatality rate was 3.5%. In the years preceding the repeal the Copyrighted Material Is the repeal of the helmet law associated with increased fatality rate among motorcyclists? average fatality rate for motorcyclists was 3.0%. Use the results of the study to answer the following research question: 1 Data are from deepblue.lib.umich.edu Explore the Observed Data 1. Do these data suggest that the repeal of the law is associated with increased fatalities? Explain. Set up a Model 2. Set up a Sampler (model) that can be used to appropriately answer the research question. Copy and paste the Sampler window into your word-processed document. Simulate from the Model Use TinkerPlots to simulate 500 trials. Copyrighted Material Evaluate the Model 1. Position the divider tool in order to quantify the strength of evidence. Paste the plot of the distribution of simulated proportions into your word-processed document. Make sure the divider tool is correctly positioned in the plot. 2. Quantify the amount of evidence the observed result provides in supporting the hypothesized model (i.e., compute the p-value). 3. Based on your answers to the previous two questions, is the observed result likely to occur by random chance? Explain. Answer the Research Question 4. Based on your analysis of these data, is there evidence that the repeal of the law is associated with increases the fatality rate ? Copyrighted Material