Question

1.

x	P(x)
0	0.1
1	0.15
2	0.25
3	0.5

Find the standard deviation of this probability distribution. Give your answer to at least 2 decimal places

2. The student council is hosting a drawing to raise money for scholarships. They are selling tickets for $7 each and will sell 700 tickets. There is one $2,000 grand prize, two $200 second prizes, and ten $30 third prizes. You just bought a ticket. Find the expected value for your profit. Round to the nearest cent.

$

Answer 1

x	p	xp	x^2	x^2 * p
0	0.1	0	0	0
1	0.15	0.15	1	0.15
2	0.25	0.5	4	1
3	0.5	1.5	9	4.5
6	1	2.15		5.65

We bought a ticket at $ 7

Expected winning amount = $ 3.86

expected profit = expected winning amount - the actual amount of ticket

= $ 3.86 - $ 7

= -3.14

Expected profit is $ -3.14

So it is an expected loss of $3.14