Please help me out with this problem.

Question

A manufacturer of toasters noticed that 80% of their toasters have no flaws, 15% of their toasters have one flaw, and 5% have two flaws. If a customer buys a new toaster from this manufacturer, the expected number of flaws will be...

1. 0.15
2. 0.20
3. 0.25
4. 1

Answer 1

You multiply the number of flaws by the probability and sum these

So

Flaws Probability

0 80% = 0.80

1 0.15

2 0.05

So 0 x 0.80 + 1 x 0.15 + 2 x 0.05 = 0.25