苏珊（Susan）想在后港（Hougang）的某个熟食中心开一个食品摊位，并打算采访 50 个人关于他们的食物偏好 and 平均食物支出。

(i)
确定一种合适的抽样方法，并说明选择它的理由。
(ii)
描述苏珊如何实施（i）中选择的方法。

总体与简单随机样本 English

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完整解法

10(i)

1. Identify an appropriate sampling method.

Quota sampling.

2. Justify the choice by comparing it with simple random sampling and highlighting its advantages.

A sampling frame of all the people visiting the food centre is not available, which makes simple random sampling impossible. Quota sampling does not require a sampling frame and can ensure that the sample is representative of the patrons' demographics (e.g., by age or gender).

答案

Quota sampling (or Systematic sampling).

A sampling frame (a complete list of all the people visiting the food centre) is not available, making simple random sampling impossible. Quota sampling does not require a sampling frame and allows Susan to collect a sample that is representative of the demographics (e.g., age groups or gender) of the food centre's patrons.

10(ii)

1. Describe the systematic selection mechanism at the location.

Susan can station herself at the entrance of the food centre. She selects a random starting person from the first $k$ people, and subsequently approaches every $k$ -th person who enters the food centre.

2. State the completion condition for the sample.

She continues this selection process until she has successfully gathered responses from exactly 50 people.

答案

Susan can stand at the main entrance of the food centre. She approaches every $k$ -th person (for example, every 5th person) who walks past her to be interviewed. She continues this process, ignoring those who decline, until she has successfully interviewed a total of 50 people.

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苏珊（Susan）想在后港（Hougang）的某个熟食中心开一个食品摊位，并打算采访 50 个人关于他们的食物偏好 and 平均食物支出。

完整解法

10(i)

10(ii)

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