1. Finding Probabilities
How are probabilities found?

2. Three Ways…
THEORETICAL – for example drawing a king from a pack of cards. This is called using equally likely outcomes.
SURVEY OR EXPERIMENTAL – we can’t use equally likely outcomes to calculate the probability of an event such as buying a certain brand of fizzy drink. Instead we collect experimental data and estimate the probability. The more data collected the better the estimate.
HISTORICAL – the probability of an event occurring such as an earthquake can only be estimated by looking at past data and making a “best guess”.

3. Which of the three methods would we use…?
Someone in this class will go abroad for a holiday this year.
You will win the national lottery.
Your bus home will be late.
It will snow on Christmas day.
You will pick a red seven from a pack of cards.