Outcomes can be predicted mathematically using statistics or probability. To determine the probability of an event occurring, take the number of the desired outcome, and divide it by the possible number of outcomes. With statistics, an outcome is predicted based on recorded behavior.
The theoretical probability of flipping a head after tossing a coin is 1/2, as obtained from dividing one (desired outcome) by two (head plus tail). When using statistics, one would first toss the coin a number of times and record the outcome each time. If "head" appeared 19 times after flipping the coin 36 times, the probability of flipping "head" would be 19/36, or 53 percent.
The validity and precision of such predictions depends on statistical reliability. When studying the efficacy of blood pressure medication in mice, a person would want to carry out a number of trials before trying it out on humans. Predictions for effectiveness of the drug on humans would be more reliable if trials in mice produce consistent results at different times.
Statistics have also been employed to predict outcomes of football matches for betting purposes. For instance, many pundits and fans thought Brazil would win the 2014 FIFA World Cup because statistics showed it had won many times against European opponents before.