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Ebook Statistical techniques in business & economics (17th edition): Part 2

(BQ) Part 2 book "Statistical techniques in business & economics" has contents: Analysis of variance, correlation and linear regression, multiple regression analysis, statistical process control and quality management, an introduction to decision theory, index numbers,.and other contents. | www.downloadslide.com Two-Sample Tests of Hypothesis 1 1 © JGI/Blend Images LLC RF GIBBS BABY FOOD COMPANY wishes to compare the weight gain of infants using its brand versus its competitor’s. A sample of 40 babies using the Gibbs products revealed a mean weight gain of 7.6 pounds in the first three months after birth. For the Gibbs brand, the population standard deviation of the sample is 2.3 pounds. A sample of 55 babies using the competitor’s brand revealed a mean increase in weight of 8.1 pounds. The population standard deviation is 2.9 pounds. At the .05 significance level, can we conclude that babies using the Gibbs brand gained less weight? (See Exercise 3 and LO11-1.) LEARNING OBJECTIVES When you have completed this chapter, you will be able to: LO11-1 Test a hypothesis that two independent population means are equal, assuming that the population standard deviations are known and equal. LO11-2 Test a hypothesis that two independent population means are equal, with unknown population standard deviations. LO11-3 Test a hypothesis about the mean population difference between paired or dependent observations. LO11-4 Explain the difference between dependent and independent samples. www.downloadslide.com 354 CHAPTER 11 INTRODUCTION Chapter 10 began our study of hypothesis testing. We described the nature of hypothesis testing and conducted tests of a hypothesis in which we compared the results of a single sample to a population value. That is, we selected a single random sample from a population and conducted a test of whether the proposed population value was reasonable. Recall in Chapter 10 that we selected a sample of the number of desks assembled per week at Jamestown Steel Company to determine whether there was a change in the production rate. Similarly, we sampled the cost to process insurance claims to determine if cost-cutting measures resulted in a mean less than the current $60 per claim. In both cases, we compared the results of a single .