Ms. Sarah Davies and her spouse, John, have 2015 medical expenses which total $4,330. While Ms. Davies has 2015 Net income for tax purposes of $150,000, John has no income during the year. They have three children. Martha is 12, has medical expenses of $4,600 and no net income. Max is 21, has 2015 medical expenses of $8,425 and net income for tax purposes of $8,250. Michelle is 23, has 2015 medical expenses of $120 and net income for tax purposes of $6,000. Ms. Davies pays all of the medical expenses. Required: Determine Ms. Davies medical expense tax credit for 2015.