In statistics, a sample is a group of items or values that are to represent a population. It is typically used because collecting data for larger populations is often inconvenient.

A sample statistic is a number that can be calculated from sample data.

An example of a sample statistic is the mean of 5 VCE students in a class of 50. In this instance, sample mean would be the average heights of 5 students. On the other hand, the population mean, The symbol $\mu$ would be the average height of all 50 students. Since any combination of 5 students can be used, the sample mean, $\bar{x}$, is varies from sample to sample.

## Simple Random Sample (SRS)

Simple random sampling is a method of obtaining a representative sample for the population. In an SRS, the selection of the sample is completely unbiased. i.e. each member of the population has an equal chance of being selected. Typical methods of random sampling involve the use of a random number generator.