BIOSTATS CHAP 2.2

probability sampling

It refers to a sampling method that uses some form of random selection.

lottery method

table of random number

RAN function of calculator

software

simple random sampling

lottery method

It is the most commonly used method in drawing sample. This method is easy to carry out especially if both population and sample are small, but can be tedious and time consuming for large populations or large samples.

table of random number

It is the sets of random digits arranged in-groups both horizontally and vertically.

RAN function of the calculator

It is a function in a scientific calculator that has the capacity to generate the random samples.

software

It refers to any program used to generate random samples using computer.

systematic random sampling

This method of probability sampling involves the selection of the desired sample in a list by arranging systematically or logically in either alphabetically arrangement or any acceptable arrangement.

systematic random sampling

This sampling is a method of selecting a sample by taking every kth individual from the ordered population, where only the first individual was selected at random and the rest will be selected in a systematic manner. If the end of the list is reached before the desired samples, treat the population as in circular list.

k=N/n

The formula for k is:

k

sampling interval

N

population size

n

sample size

cluster sampling

The probability sampling in which the population is divided into a number of non-overlapping strata, so that the samples within a stratum are more or less homogeneous and samples among strata are heterogeneous.

cluster sampling

From a population of clusters, sample clusters are selected and a sample is taken from selected sample clusters. The sample obtained is called a cluster sample. The clusters are the primary units and the individuals within the cluster are the secondary units.

multi-stage sampling

This sampling named multistage because sampling is done in stages. In this method, the population is first divided into a number of first-stage from which sample is drawn.

non-probability sampling

it refers to a sampling method which does not involve random selection, i.e., the probabilities of selection are not specified for each individual in the population.

accidental/haphazard sampling

refers to a non-probability sampling method wherein the samples are selected by chance or availability

judgemental or purposive sampling

refers to a non-probability sampling wherein the samples are chosen based on an expert's opinion.

convenience sampling

refers to an non-probability sampling wherein the samples are readily or easily accessible.

quota sampling

it is a non-probability sampling wherein the samples are chosen according to some fixed quota, whereby the concerned is to come up with the required number of samples no matter how they are selected.

snowball sampling

refers to an non-probability sampling method wherein the samples are obtained by a way that an individual to be included was identified by an individual who was previously included.