Using Rstudio 10.2 Identifying Good System Administrators. A management consultant is studying the roles played by experience and training in a system administrator's ability to complete a set of tasks in a specified amount of time. In particular, she is interested in discriminating between administrators who are able to complete given tasks within a specified time and those who are not. Data are collected on the performance of 75 randomly selected administrators. They are stored in the file SystemAdminis- trators.jmp. The variable Experience measures months of full-time system administrator experi- ence, while Training measures the number of relevant training credits. The dependent variable Completed task is either Yes or No, according to whether or not the admin- istrator completed the tasks. a. Create a scatterplot of Experience versus Training using color or symbol to differ- entiate programmers who complete the task from those who did not complete it. Which predictor(s) appear(s) potentially useful for classifying task completion? b. Run a logistic regression model with both predictors using the entire dataset as training data. Model the probability of Completed Task = Yes. Among those who complete the task, what is the percentage of programmers who are incorrectly classified as failing to complete the task? PROBLEMS 243 c. To decrease the percentage in part (b), should the cutoff probability be increased or decreased? d. How much experience must be accumulated by a programmer with four years of training before his or her estimated probability of completing the task exceeds 50%?