Probability Sampling Methods

Probability Sampling Methods

• The probability of being selected into the sample is known and equal for all members of the population in probability sampling.
• Simple random sampling is a type of probability sampling where every member of the population has an equal chance of being selected.
• The probability of selection is calculated using the formula: Probability of selection = [Sample Size] / Population size

Simple Random Sampling

• The "blind draw" method involves blindly choosing participants by their names or some other unique designation.
• The table of random numbers method uses a listing of numbers with assured random order, making it difficult to see any systematic sequence of numbers.

Simple Random Sampling Procedure

• Steps involved in simple random sampling include:
  • Accessing the population as per the specified definition
  • Drawing the sample in a two-phase process
  • Validating the sample by comparing its demographic profile with a known profile
  • Resampling if necessary

Systematic Sampling

• Systematic sampling is a type of probability sampling that employs a random starting point and a fixed interval to select participants.
• It is often preferred over simple random sampling due to its economic efficiency and ease of application.

Non-Probability Sampling Methods

• Judgment samples require the researcher to use their judgment or educated guess to select participants who represent the population.
• Referral sampling involves using existing respondents to refer additional participants, often used in industrial marketing research situations.
• Quota samples establish a specific quota for various types of individuals to be interviewed, determined by research objectives and key characteristics.

Sampling Process

• Steps involved in the sampling process include:
  • Accessing the population
  • Drawing the sample
  • Validating the sample
  • Resampling if necessary