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Tutorial 7 Solution

# Tutorial 7 Solution - AB103 Statistical and Quantitative...

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AB103: Statistical and Quantitative Methods Tutorial 7: Solutions 1. A parameter is a numerical descriptive measure of a population, e.g. population mean μ, population standard deviation σ . The value of a parameter is fixed for a specific population, though often not known. A statistic is a numerical descriptive measure of a sample taken from a population, e.g., sample mean X and sample standard deviation s. The value a statistic changes from sample to sample. Inference is a process of using sample statistics to make inferences about population parameters. If samples of size n are taken randomly from a population, then the value of the sample statistic changes from sample to sample in a random fashion (i.e., the sample statistic is a random variable). The probability distribution of the sample statistic is called a sampling distribution. 2. Population distribution: Age 17 18 19 20 Percentage % 0.2 0.3 0.2 0.3 a) μ = 17*0.2 + 18*0.3 + 19*0.2 + 20*0.3 = 18.6 σ 2 = 17 2 *0.2 + 18 2 *0.3 + 19 2 *0.2 + 20 2 *0.3 – μ 2 = 1.24 b) Possible Samples

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Tutorial 7 Solution - AB103 Statistical and Quantitative...

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