“In probability sampling the decision whether a particular element is included in the sample or not, is governed by chance alone”

Absolutely, in probability sampling, the selection of elements for inclusion in the sample is based on chance alone.

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This approach ensures that each element in the population has a known and non-zero probability of being selected for the sample, providing a solid foundation for making statistical inferences about the entire population.

Key characteristics of probability sampling include:

  1. Random Selection:
  • Elements are chosen randomly, where each element has a known probability of being selected. This randomness helps avoid bias in the selection process.
  1. Equal Chance of Selection:
  • Every element in the population has an equal chance of being chosen for the sample. This principle is fundamental to the fairness of the sampling process.
  1. Representativeness:
  • Because of the random selection, the sample is more likely to be representative of the overall population. This allows for generalizing findings from the sample to the entire population.
  1. Statistical Inference:
  • Probability sampling enables the use of statistical techniques to make inferences about population parameters based on sample statistics. This is a key advantage for drawing reliable conclusions.
  1. Precision and Reliability:
  • The chance-based selection ensures that the sample is not systematically biased, leading to more precise and reliable estimates of population characteristics.

Common probability sampling methods include:

  • Simple Random Sampling: Each element is selected independently and with an equal probability. This can be done with or without replacement.
  • Stratified Random Sampling: The population is divided into strata, and then random samples are taken from each stratum.
  • Systematic Sampling: Elements are selected at regular intervals after a random start, determined by dividing the population size by the desired sample size.
  • Cluster Sampling: The population is divided into clusters, and a random sample of clusters is selected. Then, all elements within the chosen clusters are included in the sample.

Probability sampling contrasts with non-probability sampling, where the selection process doesn’t rely on known probabilities and may introduce bias. Probability sampling methods are widely used in scientific research, market research, and various fields where representative samples are essential for making accurate and generalizable conclusions.