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Ch. 1 - Introduction to Statistics
Triola - Elementary Statistics 14th Edition
Triola14th EditionElementary StatisticsISBN: 9780137366446Not the one you use?Change textbook
All textbooksTriola 14th EditionCh. 1 - Introduction to StatisticsProblem 1.1.10
Chapter 1, Problem 1.1.10

In Exercises 9–12, determine whether the sampling method appears to be sound or is flawed.


Clinical Trials Researchers at Yale University conduct a wide variety of clinical trials by using subjects who volunteer after reading advertisements soliciting paid volunteers.

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Identify the sampling method used: In this case, the sampling method involves recruiting volunteers through advertisements, which is a form of convenience sampling.
Evaluate the potential biases: Consider whether the sample might be biased. Since the sample consists of volunteers who respond to advertisements, it may not be representative of the general population.
Consider the implications of volunteer bias: Volunteers might have different characteristics compared to non-volunteers, such as being more health-conscious or having more free time, which could affect the results of the clinical trials.
Assess the impact on generalizability: Determine how the potential biases might affect the ability to generalize the findings of the clinical trials to a broader population.
Conclude on the soundness of the sampling method: Based on the analysis of potential biases and generalizability, decide whether the sampling method is sound or flawed for the intended purpose of the clinical trials.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Sampling Method

The sampling method refers to the process used to select individuals from a population to participate in a study. In this context, the method involves recruiting volunteers through advertisements, which may introduce bias as it relies on self-selection, potentially affecting the representativeness of the sample.
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Sampling Distribution of Sample Proportion

Volunteer Bias

Volunteer bias occurs when individuals who choose to participate in a study differ in significant ways from those who do not, potentially skewing the results. In clinical trials, volunteers might have different health characteristics or motivations compared to the general population, impacting the validity of the findings.

Representativeness

Representativeness is the degree to which a sample accurately reflects the characteristics of the population from which it is drawn. A sound sampling method should ensure that the sample is representative, minimizing bias and allowing for generalization of results to the broader population. In this case, reliance on volunteers may compromise representativeness.
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