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Probability is the chance that a given event will occur in an experiment.  You can use probability to predict outcomes.

Example:  From a normal coin, what is the probability of flipping heads?

A coin contains one head and one tail,
 so the probability will be 1/2.

To predict how many times you may flip heads, multiply probability of flipping heads by the number of trials.

Probability (head) = 1/2

1/2 x 10 = 5

Prediction: about 5 times

You would expect to flip 5 heads in 10 tries.



Predict how many times you will spin the number 1 in 40 spins.

Probability (1) = 1/4

1/4 x 40 = 10

Prediction: about 10 times

You would expect to spin the number 1, 10 times in 40 tries.


Remember: First make a prediction, then complete all the trials, and finally compare the prediction and actual results.

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