Created by Culan O'Meara
over 6 years ago


Question  Answer 
Fundamental Principle of Counting  When there are m ways to do one thing, and n ways to do another, then there are m×n ways of doing both. For example, if there are 3 colours and 3 sizes of tshirt, then there are 9 combinations available. 
Sample Space  The set of all possible outcomes of an experiment. There are three types: list, tree diagram and twoway table 
Twoway table  A sample space for showing the combined outcomes of two independent events. For example a throw of a die and picking a card from a pack. 
Probability Scale  
Trial  Any particular performance of a random experiment, e.g. one roll of a die 
Outcome  A result of a trial 
Event  Occurrence of one or more specified outcomes. If we are looking to land an even number on a die, rolling a 6 would be an example of an event 
Relative Frequency = Experimental Probability 
An estimate of the probability of an event occurring based on outcomes of trials already carried out
Image:
rel_freq (image/jpeg)

Fair = Unbiased  If all outcomes are equally likely to occur then the trial or experiment is considered to be fair or unbiased. For example, a fair die should land on heads around 50% of the time 
Theoretical Probability = Probability  Probability of an event happening found by dividing the number of desirable outcomes by the total number of possible outcomes. E.g. Probability of rolling a 3 on a fair die is 1/6 as there is one favourable outcome and six possible outcomes 
Expected Frequency  Estimate of how many times we'd expect an event to happen over a set number of trials Expected Frequency = (no of trials) x (relative frequency or probability) 
Tree Diagram 
Used to write down all possible combinations for two or more trials. Example below is for flipping a coin two times
Image:
tree_diagram (image/jpeg)
