WJEC Maths for AS: Applied sample

15 Summary Summary Check you know the following facts: Population – all members of the set that is being studied or has data collected about it. Sample – a smaller subset of the population and is used to draw conclusions about the population. Sampling techniques Simple random sampling – each item in the population is given a number and then the required number of items in the sample are picked at random using calculator, program, website. Systematic sampling – the sampling interval is found by dividing the population by the sample size. You then pick a random number within this sample size and start from that as the ϐirst item in the sample. You then add the sampling interval to the random number to get the next number in the sample. This is repeated until you have the required sample. Opportunity sampling – here you decide on the sample size and simply use the most convenient way of collecting the sample (e.g. friends, relatives, classmates, work colleagues, etc).