Understanding Basic Statistics
8th Edition
ISBN: 9781337558075
Author: Charles Henry Brase, Corrinne Pellillo Brase
Publisher: Cengage Learning
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Chapter 8.2, Problem 22P
Baseball: Home Run Percentage The home run percentage is the number of home runs per 100 times at bat. A random sample of 143 professional baseball players gave the following data for home run percentages (Reference: The Baseball Encyclopedia, Macmillan).
| 1.6 | 2.4 | 1.2 | 6.6 | 2.3 | 0.0 | 1.8 | 2.5 | 6.5 | 1.8 |
| 2.7 | 2.0 | 1.9 | 1.3 | 2.7 | 1.7 | 1.3 | 2.1 | 2.8 | 1.4 |
| 3.8 | 2.1 | 3.4 | 1.3 | 1.5 | 2.9 | 2.6 | 0.0 | 4.1 | 2.9 |
| 1.9 | 2.4 | 0.0 | 1.8 | 3.1 | 3.8 | 3.2 | 1.6 | 4.2 | 0.0 |
| 1.2 | 1.8 | 2.4 |
(a) Use a calculator with mean and standard deviation keys to verify that
(b) Compute a 90% confidence interval for the population mean µ of home run percentage for all professional baseball players. Hint: If you use Table 4 of the Appendix, be sure to use tile closest d.f. that is smaller.
(c) Compute a 99% confidence interval for the population mean µ of home run percentages for all professional baseball players.
(d) Interpretation The home run percentages for three professional players are
Tim Huelett, 2.5 Herb Hunter, 2.0 Jackie Jensen, 3.8
Examine your confidence intervals and describe how the home run percentages for these players compare to the population average.
(e) Check Requirements In previous problems, we assumed the x distribution was normal or approximately normal. Do we need to make such an assumption in this problem? Why or why not? Hint: See the central limit
theorem in Section 7.5.
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Chapter 8 Solutions
Understanding Basic Statistics
Ch. 8.1 - In Problems 1-8, answer true or false. Explain...Ch. 8.1 - In Problems 1-8, answer true or false. Explain...Ch. 8.1 - In Problems 1-8, answer true or false. Explain...Ch. 8.1 - In Problems 1-8, answer true or false. Explain...Ch. 8.1 - In Problems 1-8, answer true or false. Explain...Ch. 8.1 - In Problems 1-8, answer true or false. Explain...Ch. 8.1 - In Problems 1-8, answer true or false. Explain...Ch. 8.1 - In Problems 1-8, answer true or false. Explain...Ch. 8.1 - Critical Thinking Sam computed a 95% confidence...Ch. 8.1 - Critical Thinking Sam computed a 90% confidence...
Ch. 8.1 - Basic Computation: Confidence Interval Suppose x...Ch. 8.1 - Basic Computation:Confidence Interval Suppose x...Ch. 8.1 - Basic Computation: Sample Size Suppose x has a...Ch. 8.1 - Basic Computation: Sample Size Suppose x has a...Ch. 8.1 - Zoology: Hummingbirds Allen's hummingbird...Ch. 8.1 - Diagnostic Tests: Uric Acid Overproduction of uric...Ch. 8.1 - Diagnostic Tests: Plasma Volume Total plasma...Ch. 8.1 - Agriculture: Watermelon What price do farmers get...Ch. 8.1 - FBI Report: Larceny Thirty small communities in...Ch. 8.1 - Confidence Intervals: Values of A random sample...Ch. 8.1 - Confidence Intervals: Sample Size A random sample...Ch. 8.1 - Ecology: Sand Dunes At wind speeds above 1000...Ch. 8.1 - Profits: Banks Jobs and productivity! How do banks...Ch. 8.1 - Prob. 24PCh. 8.1 - Ballooning: Air Temperature How hot is the air in...Ch. 8.2 - Use Table 4 of the Appendix to find tc for a 0.95...Ch. 8.2 - Use Table 4 of the Appendix to find tc for a 0.99...Ch. 8.2 - Use Table 4 of the Appendix to find tc for a 0.90...Ch. 8.2 - Use Table 4 of the Appendix to find tc for a 0.95...Ch. 8.2 - Statistical Literacy Students t distributions are...Ch. 8.2 - Statistical Literacy As the degrees of freedom...Ch. 8.2 - Critical Thinking Consider a 90% confidence...Ch. 8.2 - Critical Thinking Consider a 90% confidence...Ch. 8.2 - Critical Thinking Lorraine computed a confidence...Ch. 8.2 - Critical Thinking Lorraine was in a hum when she...Ch. 8.2 - Basic Computation: Confidence Interval Suppose x...Ch. 8.2 - Basic Computation: Confidence Interval A random...Ch. 8.2 - In Problems 13-19. assumethat the population of x...Ch. 8.2 - In Problems 13-19. assumethat the population of x...Ch. 8.2 - In Problems 13-19. assume that the population of x...Ch. 8.2 - In Problems 13-19, assume that the population of x...Ch. 8.2 - In Problems 13-19, assume that the population of x...Ch. 8.2 - In Problems 13-19, assume that the population of x...Ch. 8.2 - 19 Critical Thinking: Boxplots and Confidence...Ch. 8.2 - Crime Rale: Denver The following data represent...Ch. 8.2 - Finance: P/E Ratio The price of a share of stock...Ch. 8.2 - 22.
Baseball: Home Run Percentage The home run...Ch. 8.2 - Expand Your knowledge: Alternate Method for...Ch. 8.3 - Statistical Literacy For a binomial experiment...Ch. 8.3 - Statistical Literacy In order to use a normal...Ch. 8.3 - Critical Thinking Results of a poll of a random...Ch. 8.3 - Critical Thinking You want to conduct a survey to...Ch. 8.3 - Critical Thinking Jerry tested 30 laptop computers...Ch. 8.3 - Critical Thinking: Brain Teaser A requirement for...Ch. 8.3 - Basic Computation: Confidence Interval for p...Ch. 8.3 - Basic Computation: Confidence Interval for p...Ch. 8.3 - Basic Computation: Sample Size What is the minimal...Ch. 8.3 - Basic Computation: Sample Size What is the minimal...Ch. 8.3 - Myers-Briggs: Actors Isabel Myers was a pioneer in...Ch. 8.3 - Myers-Briggs: Judges In a random sample of 519...Ch. 8.3 - Navajo Lifestyle: Traditional Hogans A random...Ch. 8.3 - Archaeology: Pottery Santa Fe black-on-white is a...Ch. 8.3 - Health Care: Colorado Physicians A random sample...Ch. 8.3 - Law Enforcement: Escaped Convicts Case studies...Ch. 8.3 - Fishing: Barbless Hooks In a combined study of...Ch. 8.3 - Focus Problem: Trick or Treat In a survey of a...Ch. 8.3 - Marketing: Customer Loyalty In a marketing survey,...Ch. 8.3 - Marketing: Bargain Hunters In a marketing survey,...Ch. 8.3 - Lifestyle: Smoking In a survey of 1000 large...Ch. 8.3 - Opinion Poll: Crime and Violence A NewYork...Ch. 8.3 - Medical: Blood Type A random sample of medical...Ch. 8.3 - Business: Phone Contact How hard is it to reach a...Ch. 8.3 - Campus Life: Coeds What percentage of your campus...Ch. 8.3 - Small Business: Bankruptcy The National Council of...Ch. 8.3 - Prob. 27PCh. 8.3 - Expand Your Knowledge: Plus Four Confidence...Ch. 8 - Terminology Answer true or false. The margin of...Ch. 8 - Terminology Answer true or false. A point estimate...Ch. 8 - Terminology Answer true or false. A c% confidence...Ch. 8 - Terminology Consider a student's t distribution....Ch. 8 - Statist Literacy In your own words, carefully...Ch. 8 - Critical Thinking Suppose you are told that a 95%...Ch. 8 - Critical Thinking If you have a 99% confidence...Ch. 8 - For Problems 8-12, categorize each problem...Ch. 8 - For Problems 8-12, categorize each problem...Ch. 8 - For Problems 8-12, categorize each problem...Ch. 8 - For Problems 8-12, categorize each problem...Ch. 8 - or Problems 8-12, categorize each problem...Ch. 8 - Telephone Interviews: Survey The National Study of...Ch. 8 - Telephone Interviews: Survey How large a sample is...Ch. 8 - Archaeology: Pottery Three-circle, red-on-white is...Ch. 8 - Archaeology: Pottery Consider the three-circle,...Ch. 8 - Expand Your Knowledge: Two Confidence Intervals...Ch. 8 - Garrison Bay is a small hay in Washington stale. A...Ch. 8 - Examine Figure 8-7. Fall Back " (a) Of the 1024...Ch. 8 - Examine Figure 8.-8, "Coupons: Limited Use." (a)...Ch. 8 - In this chapter, we have studied confidence...Ch. 8 - Throughout Chapter 8. we have used the normal...Ch. 8 - When the results of a survey or a poll are...
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