Load ISLR package to R.

Use "Credit" data which is embeded into ISLR package and consists of 400 rows.

For your information, the first six lines of the Credit data has been printed here.

> head(Credit)

IDIncomeLimit Rating Cards Age Education Gender Student Married Ethnicity Balance

1114.891360628323411MaleNoYesCaucasian333

22106.025664548338215FemaleYesYesAsian903

33104.593707551447111MaleNoNoAsian580

44148.924950468133611FemaleNoNoAsian964

5555.882489735726816MaleNoYesCaucasian331

6680.180804756947710MaleNoNoCaucasian1151

Choose the best 4 parameters to predict credit balance and provide the equation.