Final answer:
To find the probability of getting at least 13 heads when flipping a coin 20 times, we use the formula for the probability of getting exactly k heads in n coin flips and calculate the probabilities for each case.
Step-by-step explanation:
In order to find the probability of getting at least 13 heads when flipping a coin 20 times, we need to calculate the probability of getting exactly 13, 14, 15, 16, 17, 18, 19, or 20 heads and add them together.
The probability of getting exactly k heads in n coin flips is given by the formula:
P(k heads) = C(n, k) * (0.5)^n
Where C(n, k) is the number of combinations of n items taken k at a time.
Using this formula, we can calculate the probabilities for each case and add them up to find the final probability:
P(13 heads) = C(20, 13) * (0.5)^20
P(14 heads) = C(20, 14) * (0.5)^20
...
P(20 heads) = C(20, 20) * (0.5)^20
Final probability = P(13 heads) + P(14 heads) + ... + P(20 heads)