The outcome space is TT, TH, HT, HH: 4 outcomes in all.
{One head} = {TH, HT} with prob = 2/4 = 1/2
{No heads} = {TT} with prob 1/4
So E = 2*Pr(one H) - 4*Pr(no H) = 2*(1/2)-4*(1/4) = 1 - 1 = 0
This is a good bet to take. Your expected payout is 0.5 each round of the 2 tosses. The possible outcomes from 2 tosses: HT, HH, TT, TH. The probability that heads comes up is 3 in 4 (.75). The probability that heads does not come up is 1 in 4 (.25). Your expected payout is: (2 * .75) + (-4 * .25) = 1.5 - 1 = 0.5
There is a .25 chance that no heads will come up. (1/2*1/2=.25) Therefore, there is a .75 chance that one or more heads will come up. Value of game = .75*$2-.25*$4=$1.5-$1=$.50 Over time, you should come out ahead.
7/10
Eight.
The odds are 50/50. A tossed coin does not have a memory.
This is a good bet to take. Your expected payout is 0.5 each round of the 2 tosses. The possible outcomes from 2 tosses: HT, HH, TT, TH. The probability that heads comes up is 3 in 4 (.75). The probability that heads does not come up is 1 in 4 (.25). Your expected payout is: (2 * .75) + (-4 * .25) = 1.5 - 1 = 0.5
mean = 5, variance = 5
There is a .25 chance that no heads will come up. (1/2*1/2=.25) Therefore, there is a .75 chance that one or more heads will come up. Value of game = .75*$2-.25*$4=$1.5-$1=$.50 Over time, you should come out ahead.
The chance is 3.5/7.
1/4
0.5, 1/2, 50% The probability for heads versus tails does not change based on the amount of times the coin is tossed. It will always be a 50% chance.
1/2
7/10
The probability of a heads is 1/2. The expected value of independent events is the number of runs times the probability of the desired result. So: 100*(1/2) = 50 heads
Eight.
It is (1/2)9 = 1/512
The odds are 50/50. A tossed coin does not have a memory.