OpenRevise

Maths · Edexcel Paper 1

Probability

The probability skills tested on Edexcel Paper 1: relative frequency and expected outcomes, tree diagrams, Venn diagrams and set notation, frequency trees and two-way tables, and conditional probability.

  • 5 lessons
  • Edexcel

Lessons

Ticks are remembered on this device only.

Key terms in this chapter

All 45, gathered from every lesson.

Probability
A number from 0 to 1 that measures how likely an event is.
Outcome
One possible result of an experiment.
Event
One or more outcomes that you are interested in.
Sample space
A list or table of all the possible outcomes.
Mutually exclusive
Events that cannot happen at the same time.
Relative frequency
The fraction of trials in which an event happened.
Expected frequency
The number of times an event is expected to happen, found by probability times trials.
Biased
Not fair, with some outcomes more likely than others.
Random
Chosen so that every outcome has an equal chance.
Tree diagram
A diagram with branches that shows the outcomes of events in order and their probabilities.
Branch
A line on a tree diagram showing one possible outcome and its probability.
Independent events
Events where one does not affect the probability of the other.
Dependent events
Events where the first changes the probability of the second.
Replacement
Putting an item back before the next pick.
Without replacement
Not putting an item back, so the next pick has fewer items.
At least one
One or more, found as 1 minus the probability of none.
Outcome probability
The probability of one complete path through the tree.
Product
The result of multiplying.
Set
A collection of items, written in curly brackets.
Universal set
The set of everything being considered, written \(\xi\).
Intersection
The items in both sets, written \(A \cap B\).
Union
The items in either set or both, written \(A \cup B\).
Complement
The items not in a set, written \(A'\).
Element
A member of a set.
Venn diagram
A diagram with overlapping circles showing how sets overlap.
Overlap
The region where two circles intersect.
Region
One of the separate parts of a Venn diagram.
Two-way table
A table that shows how many items have each combination of two features.
Frequency tree
A tree diagram with the number of items on each branch.
Frequency
The number of times something happens or the number of items in a group.
Row
A horizontal line of cells in a table.
Column
A vertical line of cells in a table.
Total
The sum of a row, a column or the whole table.
Grand total
The total of everything in the table.
Survey
A set of questions asked to a group of people to collect data.
Expected frequency
The number of times you expect something to happen, found as probability times the number of trials.
Conditional probability
The probability of an event given that another event has happened.
Given that
The words that mean you only look at part of the group.
Independent
Events where knowing one has no effect on the probability of the other.
Group
The set of items you are choosing from, after any given information.
Denominator
The number on the bottom of a fraction.
Tree diagram
A diagram showing outcomes in stages with probabilities on branches.
Two-way table
A table of counts sorted by two features.
Venn diagram
A diagram of overlapping sets with the number in each region.
Notation
The symbols used in mathematics, such as \(P(A \mid B)\).