A new purication unit is installed in a chemical process. Before its installation, a random sample yielded the following data about the percentage of impurity: 1 = 9.85, 5% = 6.79, and n1 2 10. After installation, a random sample resulted in 2 = 8.08, 5% = 6.18, and n2 2 8. a) Can you conclude that the two variances are equal? Use a = 0.05. b) Can you conclude that the new purification device has reduced the mean percentage of impurity? Use a = 0.05