Sampling methods
Population – consists of all individuals, items or objects under study Sample- a portion chosen from the population. Parameters - Measures in the population Statistics - Measures in a sample
Reason for taking sample Infinite population Wide survey area Results require in a short time Limited resources of money and enumaration
Sampling error- The discrepency between a parameter and its estimate due to sampling process Non-sampling error –other errors except sampling procedure Advantages of sampling -saves time and labour -Minimum budget -Only way for large and infinite
Types of sampling 1.Probability sampling – selection of sampling under known probabilities. 2. Purposive sampling – selection of sampling under a purpose. 3. Mixed sampling – partly under probability and partly under fixed sampling rule.
Sampling methods 1.Simple random sampling – all individual in the population have equal chances for selection of sample. 2.Staratified sampling – division of subgroups with homogenity and selection of random samples from each subgroups 3.Systematic sampling – the first unit selected at random - The other units got selected under some pre- designed pattern.