Use the file Dana.xlsx (located in Chapter 9 data files) to answer this question. Over the past few years the percentage of students who leave Dana College at the end of their

first year has increased. Last year, Dana started voluntary one-credit hour-long seminars with faculty to help first-year students establish an on-campus connection. If Dana is able to show that the seminars have a positive effect on retention, college administrators will be convinced to continue funding this initiative. Danas administration also suspects that first-year students with lower high school GPAs have a higher probability of leaving Dana at the end of the first year. The file Dana contains data on the 500 first-year stu- dents from last year. Each observation consists of a first-year students high school GPA, whether they enrolled in a seminar, and whether they dropped out and did not return to Dana. Create a standard partition of the data with all the tracked variables and 60% of observations in the training set and 40% in the validation set. Use logistic regression to classify observations as dropped out or not dropped out by using GPA and Seminar as input variables and Dropped as the output variable. Perform Variable Selection with the best subsets procedure with the number of best subsets equal to two.

Evaluate the logistic regression models based on their predictive accuracy on the validation set. Recommend a final model and express the model as a mathematical equation relating the output variable to the input variables.

The data analyst team realized that they jumped directly into building a predictive model without exploring the data. Using descriptive statistics and charts, investi- gate any relationships in the data that may explain the unsatisfactory result in part (a). For next years first-year class, what could Danas administration do regarding the enrollment of the seminars to better determine whether they have an effect on retention?