Probability helps us analyse daily real-world choices and patterns. When observing monthly rainfall records or tracking how often a pen is forgotten, empirical probability uses past frequencies to predict future outcomes. For complementary events, such as being in a school football team or whether it rains on a specific date like 12th April, the total probability equals 1. In experiments with distinct choices, like drawing fruit from a basket or spinning a raffle wheel, mutually exclusive outcomes allow us to add individual probabilities directly. Examine Figure 1 to see how empirical and complementary probabilities are calculated from everyday data.
- Empirical probability uses past tally data, such as monthly rainfall figures, to determine real-life likelihoods.
- An outcome occurring added to its complement failing to occur always totals exactly one.
- For non-overlapping choices, like picking an orange or a lemon, apply the addition rule of probability.
- Rotational raffle spinners calculate winning likelihoods by comparing favourable sectors against the total equal sectors available.
Check question: If the probability of a Grade 10 learner joining the school football team is , what is the probability that a learner selected at random is not in the team?
Show answer
. The sum of complementary probabilities is always . To find the probability of a learner not being in the team, subtract the probability of them joining from . Therefore, .
