Spent an average of 500 for

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: n? 7 (Weirs pg 344, 10.60) PROBLEM # 8.19 ­For a simple random sample, n=200 and p=0.34. At the 0.01 level, test H0:!! =0.40 versus H1:!! ≠0.40. PROBLEM # 8.20 ­ For a simple random sample, n=1000 and p=0.47. At the 0.05 level, test H0:!! ≥0.50 versus H1:!! <0.50. 8 PROBLEM # 8.21 A simple random sample of 300 items is selected from a large shipment, and testing reveals that 4% of he sampled items are defective. The supplier claims that no more than 2% of the items in the shipment are defective. Carry out an appropriate hypothesis test and comment on the credibility of the supplier’s claim. PROBLEM # 8.22 It has been claimed that 65% of the homeowners would prefer to hear with electricity instead of gas. A student finds that 60% of the 200 homeowners prefer electric heating to gas. In a two ­tail test at the 0.05 level of significance, can we conclude that the percentage who prefer electric heating may differ from 65%? Determine and interpret the p ­value for the test. 9 PROBLEM # 8.23 For each of the following situations, determine whether a one ­tail test or a two ­tail test would be appropriate. Describe the test, including the null and alternative hypotheses, then explain your reasoning in selecting it. a. A machine that has not been serviced for several months is producing output in which 5% of the items are defective. The machine has just been serviced and quality should now be improved. b. In a speech during her campaign for reelection, a Republican candidate claims that 55% of registered Democrats in her county intend to vote for her. c. Of those who have bought a new car in the part, a dealer has found that 70% experience three or more mechanical problems in the first four months of ownership. Unhappy with this percentage, the dealer has heavily revised the procedure by which pre ­delivery mechanical checks are carried out. PROBLEM # 8.24 What is a p ­value, and how it is relevant to hypothesis testing? 10 PROBLEM # 8.25 The p ­value for a hypothesis test has been reported as 0.03. If the test result is interpreted using the ! =0.05 level of significance as a criterion, will H0 be rejected? Explain. PROBLEM # 8.26 A hypothesis test is carried out using the ! =0.01 level of significance and H0 cannot be rejected. What is the most accurate statement we can make about the p ­value for this test? Understanding the Basics: Suggested Problems from the Book. 8.1 The Null and Alternative Hypotheses and Errors in Hypothesis Testing: 8.2,8.4,8.6,8.8,8.10,8.16 8.2 Type I and Type II Errors and Their Probabilities 8.3 z Tests about a population Mean (! unknown): One ­Sided Alternatives: 8.18,8.20,8.24,8.26,8.28,8.32,8.34 8.4 z Tests about a population Mean (! known): Two ­Sided Alternatives: 8.40,8.42,8.45,8.46, 8.5 t Tests about Population Mean (! unknown): 8.48,8.50,8.52,8.56, 8.6 z Tests about Population Proportion: 8.62,8.64,8.66,8.68, End of Chapter: 8.76,8.78,8.79,8.82,8.83,8.84 This statistical workbook is compiled from the following books: • • • Keller, G. (2012). Statistics for management and economics. Mason: Cengage Learning. Weiers, R. M. (2011). Introduction to Business Statistics. Mason: Cengage Learning. Gonick, L. W. (2005). The Cartoon Guide to Statistics (Vol. 1). HarperCollins. Samie’s Tips! Lesson 8 ­The Exam corner ­ TIPS and TRICKS! Hello, We are now reaching the period of “hypothesis testing”, from now on, all chapters will be about testing a hypothesis using a specific table and knowing whether you should be using the t ­tables, z ­tables, f ­table or X2 table. Understand the 7 steps and you should be okay. See you in class! Samie 11...
View Full Document

This note was uploaded on 09/30/2013 for the course COMM 215 taught by Professor Ghatri during the Fall '08 term at Concordia Canada.

Ask a homework question - tutors are online