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91Ó°ÊÓ

Laying fiber-optic cable is expensive. Cable companies want to make sure that if they extend their lines out to less dense suburban or rural areas, there will be sufficient demand and the work will be cost-effective. They decide to conduct a survey to determine the proportion of houscholds in a rural subdivision that would buy the service. They select a simple random sample of 5 blocks in the subdivision and survey each family that lives on one of those blocks. (a) What is the name for this kind of sampling method? (b) Give a possible reason why the cable company chose this method.

Short Answer

Expert verified
(a) Cluster sampling. (b) Cost-effectiveness and efficiency.

Step by step solution

01

Understand the Survey Method

The cable company has decided to select a simple random sample of blocks and survey every family on those blocks. This method is known as cluster sampling. In cluster sampling, entire groups or "clusters" are randomly selected, and then every member within the chosen clusters is surveyed.
02

Identify the Sampling Method

Using the information gathered from Step 1, we determine the sampling method. Since the company selects an entire block and surveys every family within these blocks, this is cluster sampling.
03

Analyze the Choice of Method

Cluster sampling is often used when the population is vast and geographically spread out, making individual random sampling costly and challenging. The cable company likely chose this method because it reduces travel time and costs by concentrating the survey within specific areas, making the process more efficient.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Survey Method
When conducting research or gathering data, especially over a wide area, choosing the right survey method is crucial. Survey methods determine how you will collect data from your target population. There are many survey methods, but one fundamental approach is clustering.

In cluster sampling, researchers divide the population into smaller groups called clusters. Rather than surveying the entire population or selecting individuals from each part, entire groups are selected at random. All individuals within chosen clusters are surveyed. This method is particularly useful when the population is large and spread over a wide area. Clustering makes data collection more manageable.

By reducing the geographical spread of the data collection points, businesses like cable companies can streamline the survey process. Survey method decisions should consider factors like time efficiency, costs, and the reliability of results. Cluster sampling is a strategic choice when addressing wide and dispersed populations under tight constraints.
Simple Random Sample
A simple random sample (SRS) is a foundational concept in statistics used to ensure every member of a population has an equal chance of being selected. In the context of survey methods, SRS helps to avoid biases that can skew the results. This is achieved by randomly selecting individuals from the entire population without considering sub-groups or clusters.

Although the cable company in our scenario chose cluster sampling, understanding simple random sampling provides crucial insights into why clusters might be a better fit in certain situations. With SRS, all households would have had an equal chance to be surveyed, rather than focusing on specific blocks.

Simple random sampling works best in smaller, more compact areas because all parts of the population are equally represented naturally. However, in cases where the population is large, dispersed, or when logistical constraints like costs are considered, alternate methods like clustering prove beneficial.
Cost-Effectiveness Analysis
Cost-effectiveness analysis is a critical evaluation process that helps businesses and researchers decide if an approach or method is worth the investment. It compares the costs and benefits associated with a project to find the most economical solution.

In the case of the cable company, laying fiber-optic cable involves considerable expense, especially in less dense suburban or rural areas. Conducting a survey without considering cost-effectiveness could lead to inefficient spending and suboptimal results.

With cost-effectiveness analysis, the cable company can determine if the potential demand in the rural subdivision justifies the cost of surveying through cluster sampling. By focusing surveys on selected blocks, the company can reduce travel costs and time, consequently enhancing efficiency. Ultimately, this analysis helps determine the viability of extending services to a specific area, ensuring investments align with expected returns.

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