Mean = 2.
Variance = 1.
2
Out of the 16 possible outcomes for a coin tossed four times, 4 of them result in 3 Tails & 1 Head. They are: TTTH, TTHT, THTT, and HTTT.
It is 1/16.
The probability is 1/4
The odds of each coin toss are 50-50. The coin has no memory; there is no record of what the last four tosses are. EVERY toss is at 50-50 odds.
2
It is 5/32 = 0.15625
Out of the 16 possible outcomes for a coin tossed four times, 4 of them result in 3 Tails & 1 Head. They are: TTTH, TTHT, THTT, and HTTT.
It is 1/16.
It is 0.3125
The probability is 1/4
The odds of each coin toss are 50-50. The coin has no memory; there is no record of what the last four tosses are. EVERY toss is at 50-50 odds.
18 different combinations. When a coin is tossed twice there are four possible outcomes, (H,H), (H,T), (T,H) and (T,T) considering the order in which they appear (first or second). But if we are talking of combinations of the two individual events, then the order in which they come out is not considered. So for this case the number of combinations is three: (H,H), (H,T) and (T,T). For the case of tossing a die once there are six possible events. The number of different combinations when tossing a coin twice and a die once is: 3x6 = 18 different combinations.
The variance is: 6.0
What is the question?
The variance is: 0.666666666667
The probability of a fair coin to land head is 1/2. Since for 4 flips it must land heads each time, the probability of 4 heads is 1/2 * 1/2 * 1/2 * 1/2 = 1/16.