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Unformatted text preview: lecture 19, Statistical Inference Based on Two Samples 1 / 31 Comparing Two Population Means by Using Independent Samples: Variances Known zBased Confidence Interval for the Difference in Means (Variances Known) zBased Test About the Difference in Means (Variances Known) Comparing Two Population Means by Using Large, Independent Samples: Variances lecture 19, Statistical Inference Based on Two Samples Outline 1 Comparing Two Population Means by Using Independent Samples: Variances Known zBased Confidence Interval for the Difference in Means (Variances Known) zBased Test About the Difference in Means (Variances Known) 2 Comparing Two Population Means by Using Large, Independent Samples: Variances Unknown zBased Confidence Interval for the Difference in Means (Large Samples, Variances Unknown) zBased Test About the Difference in Means (Large Samples, Variances Unknown) 3 Comparing Two Population Proportions by Using Large, Independent Samples lecture 19, Statistical Inference Based on Two Samples 2 / 31 Comparing Two Population Means by Using Independent Samples: Variances Known zBased Confidence Interval for the Difference in Means (Variances Known) zBased Test About the Difference in Means (Variances Known) Comparing Two Population Means by Using Large, Independent Samples: Variances lecture 19, Statistical Inference Based on Two Samples Comparing Two Population Means by Using Independent Samples: Variances Known Motivations • Business improvement often requires making comparisons • Examples: • Compare different types of advertising campaigns • Compare the profitability of different investment portfolios • Compare different production methods • In this lecture, we discuss how to use confidence intervals and hypothesis testing to compare two populations • We compare two population means/population proportions by studying their differences. lecture 19, Statistical Inference Based on Two Samples 3 / 31 Comparing Two Population Means by Using Independent Samples: Variances Known zBased Confidence Interval for the Difference in Means (Variances Known) zBased Test About the Difference in Means (Variances Known) Comparing Two Population Means by Using Large, Independent Samples: Variances lecture 19, Statistical Inference Based on Two Samples Comparing Two Population Means by Using Independent Samples: Variances Known Sampling Distribution of the Difference of Two Sample Means • Suppose Population 1 has mean μ 1 and variance σ 2 1 • Take a random sample of size n 1 from population 1, and denote its (sample) mean and variance by ¯ X 1 and variance S 2 1 . • Suppose Population 2 has mean μ 2 and variance σ 2 2 • Take a random sample of size n 2 from population 2, and denote its (sample) mean and variance by ¯ X 2 and variance S 2 2 ....
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This note was uploaded on 12/28/2010 for the course BUSINESS A ISOM 111 taught by Professor Yingyingli during the Fall '10 term at HKUST.
 Fall '10
 YingYingLi
 Business

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