1. Maths Unit 13 - Probability
Tree Diagrams
There are 10 pencils in a box.
Seven of the pencils are HB pencils. Toby takes two pencils. 4Draw a tree diagram to show all the possible outcomes.
Draw a tree diagram to show this information
b) Work out the probability that he picks out at least one HB
Probability - The likelihood that a particular outcome will occur. This is either expressed as a fraction, decimal
or percentage.
Theoretical probability - The probability that a certain outcome will occur based on all possible outcomes.
Experimental probability - Derived from the results of experiments, the total number of successes divided by
the total number of trials.
Bias - Favouring some outcomes over others.
Key words and definitions