What elements influence the correct sample size?

Name: Problem 5, Chapter 5: Planning Research in Hospitality & Tourism
Uploaded: 2020-07-24T07:05:40-08:00
Duration: 1 min 28 s
Channel: Monique Whittaker
Description: What elements influence the correct sample size?

Key Concepts

Confidence Level

The confidence level represents the degree of certainty that the population parameter lies within the estimated interval. This concept is crucial in sample size calculation because higher confidence levels demand larger samples to ensure that the estimates are precise and reliable.

Statistical Power

Statistical power is the probability that a test will correctly reject a false null hypothesis. Higher power reduces the risk of Type II errors and usually requires a larger sample size, especially when the effect size is small, making it a key element in determining the correct sample size.

Effect Size

Effect size measures the magnitude of the difference or effect that the study aims to detect. A smaller effect size requires a larger sample to detect the difference with statistical significance, and therefore, it plays a critical role in sample size determination.

Population Variability

Population variability, or the spread of the data, directly affects the precision of the estimates derived from a sample. Higher variability necessitates a larger sample size to accurately estimate population parameters and to achieve reliable results.

Sampling Design Considerations

The design of the study, including factors like stratification, clustering, or other complex sampling methodologies, influences the effective sample size required. Adjustments for design effects are often necessary, as these factors can inflate the variance and require additional participants.

Expected Attrition or Non-response

Anticipating attrition or non-response rates is important in sample size calculation. To compensate for potential dropout or non-responses, researchers typically increase the initial sample size to ensure that the final analyzed sample is adequate to meet the study’s statistical requirements.

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