Question

Consider 4 different ways to sample a population other than a convenience sample. You will sample 60 people. Outline how exactly you are going to carry out each of those samples. You may combine several sampling techniques. Compare each of the methods and discuss the advantages and disadvantages of each with regard to validity (minimize bias) and efficiency (How long it will take? How hard it will be to carry out the sample?).

Answer 1

Sampling Technique 1: Simple Random Sampling

Let the Population Size =N

Give Identification Number starting from 1 to N randomly to each and every member of the population.

Using Statistical Random Number generator, obtain 60 Random Numbers all from 1 to N.

The set of 60 random numbers thus obtained forms the Simple Random Sample.

Advantage: This sample will be statistically valid sample satisfying the property that each individual has th same probability of selection.

Disadvantage:This involves considerable time, money, effort as it involves entire population and random sampling methodology.

Sampling Technique 2: Systematic Sampling:

Let the Population Size =N

Give Identification Number starting from 1 to N randomly to each and every member of the population.

Start arbitrarily with a number between 1 to N.

Select that number.

Increment by another arbitrary number. Select that number.

Then again increment it by that arbitrary number.

Continue the process till we get 60 numbers.

Advantage: This is slightly simpler as compared to Simple Random Sampling as it involves enumeration of members in certain intervals.

Disadvantage: The sample may not satisfy the requirement of Simple Random Sampling.

Sampling Technique 3: Stratified Sampling

Divide the population to 10 strata, each stratum containing homogeneous people.

Select 6 people from each stratum through Random Sampling.

Thus, we get sample of 60 people.

Advantage: This method is very much applicable in non - homogeneous population

Disadvantage: The sample may not satisfy the requirement of Simple Random Sampling.

Sampling Technique 4: Cluster sampling

Divide the Population into 10 clusters, such as location.

Select 1 cluster from these 10 clusters randomly.

Select 60 people all from the cluster selected.

Advantage: The method is easy to adopt since sampling is restricted to only one cluster.

Disadvantage: The sample may not satisfy the requirement of Simple Random Sampling.