How to Calculate Probability Exercises
A simple coin is one of the easiest ways to demonstrate probability. Since there is only one outcome per event out of two possible outcomes, it is easy to see why the probability of getting heads or tails will be 50 percent. There are other ways to get into slightly more complex probability calculations, such as flipping a coin a number of times and calculating the probability that at least some other number of heads will come up.
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Instructions
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Flip a coin 50 times, marking down the outcome of each flip. Unless there is some outside factor affecting the coin flip, you should notice a roughly even number of heads and tails.
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Flip the coin two times. This time, calculate the probability both flips will have the same outcome. This is done by multiplying the two individual probabilities together, symbolized by the equation P(A · B) = P(A) * P(B), which would be (0.5)(0.5) = 0.25.
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Flip the coin twice. This time, calculate the probability of getting at least one heads. This is accomplished by using the formula P(A v B) = P(A) + P(B) - P(A * B), or 0.5 + 0.5 - (0.5 * 0.5), or 0.75. Flipping the coin three times yields the probability of getting at least one heads to be 0.5 + 0.5 - (0.5 * 0.5 * 0.5) = 0.875.
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4
Roll dice to expand the probability calculations by adding four additional outcomes to each event. Rather than an expected probability of 0.5, there is one outcome out of six possibilities per die, which is 0.166. The probability of rolling at least one six when two dice are rolled is found by multiplying the possibilities of not rolling a six by each other, or 5/6 * 5/6, then subtracting this from 1, resulting in (1-25/36) or 11/36.
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References
- Photo Credit quarter on green image by Richard McGuirk from Fotolia.com
