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CIE 9709 2023 June Paper 63 Q2

A Level / CIE / S2

CIE 9709 2023 June Paper 63 Paper · Question 2

题目

Problem

A club has 264264 members, numbered from 11 to 264264. Donash wants to choose a random sample of members for a survey. In order to choose the members for the sample he uses his calculator to generate random digits. His first 2020 random digits are as follows.

1061211801214732275910612\qquad11801\qquad21473\qquad22759

(a) The numbers of the first two members in the sample are 106106 and 121121.

Write down the numbers of the next two members in the sample.

(2)

(b) To obtain the numbers for members after the 4th member, Donash starts with the second random digit, 00, and obtains the numbers 061061 and 211211.

Explain why this method will not produce a random sample.

(1)
题目中文翻译

某俱乐部有 264264 名会员,编号为 11 到 264264。Donash 想随机抽取一些会员进行调查。为了选出样本中的会员,他用计算器生成随机数字。最先生成的 2020 个随机数字如下。

1061211801214732275910612\qquad11801\qquad21473\qquad22759

(a) 样本中最先选出的两名会员的编号是 106106 和 121121。

写出样本中接下来两名会员的编号。

(2)

(b) 为了得到第 44 名会员之后的会员编号,Donash 从第二个随机数字 00 开始,得到编号 061061 和 211211。

解释为什么这种方法无法得到随机样本。

(1)
原卷通用作答要求

Answer all questions. You should use a calculator where appropriate.

You must show all necessary working clearly; no marks will be given for unsupported answers from a calculator.

Give non-exact numerical answers correct to 3 significant figures, or 1 decimal place for angles in degrees, unless a different level of accuracy is specified in the question.

请回答所有题目。适当时应使用计算器。必须清楚展示所有必要的计算过程;仅给出计算器答案而没有过程,不予评分。除非题目另有精度要求,非精确数值答案保留 3 位有效数字,以度为单位的角度保留 1 位小数。

解答

(a)

解法一

思路

展开

连续按三位分组,拒绝超过264的编号,保留有效未重复编号。

答题过程

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Grouping the digits in threes gives

106, 121, 180, 121, 473, 227,….106,\ 121,\ 180,\ 121,\ 473,\ 227,\ldots.

After 106 and 121, accept 180, reject the repeated 121 and the out-of-range 473, and then accept 227. The next two numbers are 180 and 227\boxed{180\text{ and }227}.

(b)

解法一

思路

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重用并错位读取相同随机数字,使新编号依赖已经使用的数字,不是继续产生新的随机编号。

答题过程

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The method reuses the same random digits. The new numbers therefore depend on digits already used to select earlier members, rather than being generated independently afresh, so this does not give a random sample.