Key terms & definitions

The Islamic month during which observing Muslims fast during daylight hours.

A sacred Hindu epic telling the story of Rama, including the rescue of Sita from Ravana.

The Royal Army Medical Corps, the British Army organisation whose personnel provided medical care for soldiers.

The use of a warship’s projecting ram to strike and damage an enemy vessel.

A business that keeps and raises livestock, such as cattle, using extensive grazing land.

The deterioration of fats and oils, producing unpleasant flavours and smells.

A process is random if its individual result cannot be predicted with certainty, even when the chances of its possible results are known.

Main memory that holds programs and data currently in use so that the CPU can access them.

Assigning participants to treatment groups by chance rather than by deliberate selection.

Using chance to decide which participants enter each experimental group.

Assigning participants to study conditions by chance to reduce systematic differences between the groups.

Unpredictable variation that makes repeated readings spread above and below the value that would usually be measured.

Unpredictable variation that makes repeated measurements differ and produces scatter in the data.

Variation that makes repeated measurements differ unpredictably; its effect can be reduced by taking repeats and calculating a mean.

An unpredictable variation between readings that causes results to scatter.

A possible result whose occurrence is uncertain, such as getting heads on a coin toss.

An experiment with an unpredictable individual result, even if some results are more likely than others.

Using chance to decide aspects of a study, such as participants’ allocation to conditions or the order of test items.

Motion in which molecules continually move at different speeds and in changing directions.

Continuous movement with no overall preferred direction; collisions change the directions in which gas molecules travel.

A process governed by chance, so its individual result cannot be predicted with certainty. Random outcomes need not be equally likely.

Using a programming function to produce a number that can introduce unpredictability into a program.

A list of numbers generated randomly, which can be used to select members of a numbered sampling frame.

An outcome that cannot be predicted with certainty before a trial, even though probabilities may be known.

A process whose outcome for an individual event cannot be predicted with certainty.

A process for which the exact time of an individual event cannot be predicted. In radioactive decay, it is impossible to predict exactly when a particular unstable nucleus will decay.

The unpredictable decay of individual unstable nuclei: it is not possible to know which nucleus will decay next or exactly when it will decay.

A method for sensitive questions in which a private random event determines whether a respondent gives a prescribed answer or answers honestly, allowing a proportion to be estimated without identifying individual admissions.

A sample selected by chance so that every member of the population has an equal probability of selection.

A sample selected so that every member of the population has an equal chance of selection.