大三上统计学chapter8hypothesis testing.pptx

statistics in practice ;Chapter 9 Statistics in practice;The manager of Quality Apartment has different idea about this conclusion. He thought that the phenomenon come from the random sample. It is so early to perorate that improved autos increase the mean miles-per-gallon rating and we should do Hypothesis Testing on statistics. Engineer Zhang who has passed the practitioner qualification from the Quality Apartment has learnt a lot of statistics methods .The manager of Quality Apartment asked Engineer Zhang to solve this problem. Through simple calculation, the Engineer Zhang got the conclusion that the present data can not figure the autos before and after improved have no distinct changes in miles-per-gallon rating. Therefore, how Engineer Zhang to get this conclusion?;The keystone of chapter 1、the basic theory of Hypothesis Testing 2、the form and kind of Hypothesis Testing； 3、type I and type II error； 4、Interval Testing and methods of Hypothesis Testing。 The difficulties of chapter 1、the basic theory of Hypothesis Testing； 2 、type I and type II error;9.1.1 Testing research Hypothesis The former case can be seen an example of Testing Research hypotheses Research hypothesis: the new cars will provide a mean miles-per-gallon be lower ,that is ,the average of costing gas is lower 8.48 liter In general，research hypotheses can be seen alternative Hypothesis， So we can set up following null and alternative Hypothesis ;Example: a manufacturer of soft drinks who states that two-liter containers of its products have an average of at least 67.6 fluid ounces. A sample of two-liter containers will be selected, and the contents will be measured to test the manufacture claim. In this type of hypothesis-testing situation, we generally begin by assuming that tha manufacturer’s claim is true. Using this approach ,for the soft-drink example, we would state the null and alternative hypotheses as follows. ;9.1.3 testing in Decision-Making situations;Let denote