AQA GCSE Statistics key terms

Events for which knowing whether one occurs does not change the probability of the other occurring.

Trials in which the outcome of one does not change the probabilities of the outcomes of another.

A number expressing a value relative to a reference value, usually with the reference value set to 100.

A conclusion drawn from observed data, often extending findings from a sample to a wider population.

An increase in the general level of prices over time, usually expressed as an annual percentage change.

Identifying an unusual value by looking at the data or its display, rather than applying a numerical outlier rule.

The difference between two specified deciles. The first-to-ninth interdecile range is $D_9-D_1=P_{90}-P_{10}$ and measures the spread of the middle 80%.

The difference between two specified percentiles, calculated as the higher percentile value minus the lower percentile value.

Estimating an unknown value within the range of the observed data.

Explaining what statistical diagrams and calculations mean in the context of an investigation.

The difference between the upper and lower quartiles: $\mathrm{IQR}=Q_3-Q_1$. It measures the spread of the middle 50% of the data.

The event containing outcomes that belong to both $A$ and $B$, written $A\cap B$.

A method of collecting data in which an interviewer asks a respondent questions and records their answers.

The influence of an interviewer's wording, opinions or expectations on a respondent's answers.

A process in which stages are repeated and improved in response to what has been learnt.

The probability that two events both occur, written $P(A\cap B)$ for events $A$ and $B$.

Selecting members of a population using the researcher's judgement, usually with the intention of obtaining a representative sample.

A guide explaining what the colours, shades, patterns or symbols in a diagram represent.

An experiment conducted in a controlled setting where the researcher can keep other relevant conditions constant.

A question whose wording suggests or encourages a particular answer.

The extent to which a researcher can manage the conditions and other variables in an investigation.

An association between two variables in which the points on a scatter diagram follow a straight-line pattern.

A method of estimating a value within an interval by assuming the observations are evenly spread across that interval.

A relationship represented by a straight-line pattern on a scatter diagram.

The multiplier that changes each corresponding length of one shape or solid into that of a similar shape or solid.

A straight line that summarises the overall linear pattern of points on a scatter diagram.

The value approximately one-quarter of the way through ordered data, with about 25% of values below it.