3. For the month of April, a checking account has a balance of $523 for 24 days, $2415 for 2 days, and $250 for 4 days. What is the account's mean daily balance for April? 5. A teacher gives a 20 -point test to 10 students. The scores are shown here. Find the variance and standard deviation. 18, 15, 12, 6, 8, 2, 3, 5, 20, 10