3. • Sample : A part of the whole selected with the
belief that it will represent the characteristics of
the whole.
• Sampling is a statistical technique which is used
to collect information on the basis of the
characteristics of a population.
• Statistic: Any numerical value calculated from
sample data is called statistic.
• Population: The whole or totality from which a
sample is selected/ drawn is called a population.
• Parameter: Any numerical value calculated from
population data is called parameter.
8. Simple random sample
A sample is defined to be a simple random
sample (SRS) if it is selected in such a manner
that i) each unit in the population has an equal
probability of being included in the sample and
ii) each possible sample of the same size has an
equal probability of being the sample selected.