**Population **– an entire set of individuals or items.

**Finite Population** – a population where each individual member can be given a number.

**Infinite Population** – a population where it is impossible to number each member.

**Statistic **– a random variable that is a function of known observations from a sample involving no unknown parameters.

**Sampling Distribution** – if all possible samples are taken, then the values of the statistics along with their associated probabilities will form a probability distribution called the sampling distribution.

**Sampling Frame** – a list of all the members of the population.

**Sampling Unit** – individual member or element of the population or sampling frame.

**Census **– when every member of the population is investigated.

**Sample **– a selection of items from the population that are used to represent the population.

**Critical Region** – the range of values of the test statistic that would lead you to incorrectly reject H0.

**Level of Significance** – the probability of incorrectly rejecting H0.

**Hypothesis **– a statement concerning a population parameter.

**Hypothesis Test **– A hypothesis test is a mathematical procedure to examine a value of a population parameter proposed by the null hypothesis H0 compared to the alternative hypothesis H1.

**Test statistic** – In a hypothesis test the evidence comes from a sample which is summarised in the form of a test statistic.

**Critical Value **– the boundary value of a critical region.

**One tailed test **– looks for an increase or decrease in a parameter and has one single critical value.

**Two tailed test **– looks for both an increase and a decrease in a parameter and has 2 critical values.