An automobile workshop has three new car treatment packages, each at a different price. The workshop owner estimates that 20% of his customers will purchase the first treatment package, which costs €1,500 per package; 45%

will purchase the second package, which costs €900 per package; and 35% will purchase the third package, which costs €550 per package.

a) Find the expected value of the car treatment packages costs.

b) Find the standard deviation of the car treatment packages costs.