Intro Stats
4th Edition
ISBN: 9780321826275
Author: Richard D. De Veaux
Publisher: PEARSON
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Chapter 20, Problem 20E
To determine
Explain among pooled t-test and two-sample t-test, which is better in this situation.
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Chapter 20 Solutions
Intro Stats
Ch. 20.3 - A public broadcasting station plans to launch a...Ch. 20.3 - Prob. 2JCCh. 20.4 - Prob. 3JCCh. 20.4 - Prob. 4JCCh. 20.5 - Prob. 5JCCh. 20.5 - Prob. 6JCCh. 20.5 - Prob. 7JCCh. 20.5 - Prob. 8JCCh. 20.6 - Prob. 9JCCh. 20.6 - Recall the experiment comparing patients 4 weeks...
Ch. 20.6 - Prob. 11JCCh. 20 - Canada Suppose an advocacy organization surveys...Ch. 20 - Non-profits Do people who work for non-profit...Ch. 20 - Prob. 3ECh. 20 - Prob. 4ECh. 20 - Canada, deux The information in Exercise 1 was...Ch. 20 - Prob. 6ECh. 20 - Prob. 7ECh. 20 - Prob. 8ECh. 20 - Prob. 9ECh. 20 - Prob. 10ECh. 20 - Prob. 11ECh. 20 - Prob. 12ECh. 20 - Prob. 13ECh. 20 - Athlete ages, again Using the summary statistics...Ch. 20 - Prob. 15ECh. 20 - Athlete ages, ninth inning The researchers in...Ch. 20 - Prob. 17ECh. 20 - Athlete ages, overtime Repeat the test you did in...Ch. 20 - Prob. 19ECh. 20 - Prob. 20ECh. 20 - Prob. 21ECh. 20 - Prob. 22ECh. 20 - Prob. 23ECh. 20 - Prob. 24ECh. 20 - Prob. 25ECh. 20 - Prob. 26ECh. 20 - Prob. 27ECh. 20 - Graduation The U.S. Department of Commerce...Ch. 20 - Prob. 29ECh. 20 - Carpal tunnel The painful wrist condition called...Ch. 20 - Prob. 31ECh. 20 - Prob. 32ECh. 20 - Ear infections A new vaccine was recently tested...Ch. 20 - Anorexia The Journal of the American Medical...Ch. 20 - Prob. 35ECh. 20 - Prob. 36ECh. 20 - Teen smoking A Vermont study published by the...Ch. 20 - Depression A study published in the Archives of...Ch. 20 - Birthweight The Journal of the American Medical...Ch. 20 - Politics and sex One month before the election, a...Ch. 20 - Prob. 41ECh. 20 - Prob. 42ECh. 20 - Pain Researchers comparing the effectiveness of...Ch. 20 - Gender gap Candidates for political office realize...Ch. 20 - Prob. 45ECh. 20 - Prob. 46ECh. 20 - Sensitive men In the same article from Exercise...Ch. 20 - Carbs Recently, the Gallup Poll asked 1005 U.S....Ch. 20 - Food preference GfK Roper Consulting gathers...Ch. 20 - Prob. 50ECh. 20 - Hot dogs In the July 2007 issue, Consumer Reports...Ch. 20 - Prob. 52ECh. 20 - Prob. 53ECh. 20 - Prob. 54ECh. 20 - Hot dogs, last one In Exercise 53, we saw a 90%...Ch. 20 - Third load of wash In Exercise 54, we saw a 98%...Ch. 20 - Prob. 57ECh. 20 - Prob. 58ECh. 20 - Prob. 59ECh. 20 - Prob. 60ECh. 20 - Commuting A man who moves to a new city sees that...Ch. 20 - Pulse rates A researcher wanted to see whether...Ch. 20 - 63. View of the water How much extra is having a...Ch. 20 - New construction The house sales we looked at in...Ch. 20 - Cereal sugar The data below show the sugar content...Ch. 20 - Prob. 66ECh. 20 - Prob. 67ECh. 20 - Prob. 68ECh. 20 - Prob. 69ECh. 20 - Prob. 70ECh. 20 - Prob. 71ECh. 20 - Prob. 72ECh. 20 - Prob. 73ECh. 20 - Prob. 74ECh. 20 - Prob. 75ECh. 20 - Ad campaign You are a consultant to the marketing...Ch. 20 - Prob. 77ECh. 20 - Thirsty? Researchers randomly assigned...Ch. 20 - Prob. 79ECh. 20 - Prob. 80ECh. 20 - 81. Running heats In Olympic running events,...Ch. 20 - Prob. 82ECh. 20 - Tees Does it matter what kind of tee a golfer...Ch. 20 - Golf again Given the test results on golf tees...Ch. 20 - Music and memory Is it a good idea to listen to...Ch. 20 - Rap Using the results of the experiment described...
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- (a) What is a bimodal histogram? (b) Explain the difference between left-skewed, symmetric, and right-skewed histograms. (c) What is an outlierarrow_forward(a) Test the hypothesis. Consider the hypothesis test Ho = : against H₁o < 02. Suppose that the sample sizes aren₁ = 7 and n₂ = 13 and that $² = 22.4 and $22 = 28.2. Use α = 0.05. Ho is not ✓ rejected. 9-9 IV (b) Find a 95% confidence interval on of 102. Round your answer to two decimal places (e.g. 98.76).arrow_forwardLet us suppose we have some article reported on a study of potential sources of injury to equine veterinarians conducted at a university veterinary hospital. Forces on the hand were measured for several common activities that veterinarians engage in when examining or treating horses. We will consider the forces on the hands for two tasks, lifting and using ultrasound. Assume that both sample sizes are 6, the sample mean force for lifting was 6.2 pounds with standard deviation 1.5 pounds, and the sample mean force for using ultrasound was 6.4 pounds with standard deviation 0.3 pounds. Assume that the standard deviations are known. Suppose that you wanted to detect a true difference in mean force of 0.25 pounds on the hands for these two activities. Under the null hypothesis, 40 = 0. What level of type II error would you recommend here? Round your answer to four decimal places (e.g. 98.7654). Use a = 0.05. β = i What sample size would be required? Assume the sample sizes are to be equal.…arrow_forward
- = Consider the hypothesis test Ho: μ₁ = μ₂ against H₁ μ₁ μ2. Suppose that sample sizes are n₁ = 15 and n₂ = 15, that x1 = 4.7 and X2 = 7.8 and that s² = 4 and s² = 6.26. Assume that o and that the data are drawn from normal distributions. Use απ 0.05. (a) Test the hypothesis and find the P-value. (b) What is the power of the test in part (a) for a true difference in means of 3? (c) Assuming equal sample sizes, what sample size should be used to obtain ẞ = 0.05 if the true difference in means is - 2? Assume that α = 0.05. (a) The null hypothesis is 98.7654). rejected. The P-value is 0.0008 (b) The power is 0.94 . Round your answer to four decimal places (e.g. Round your answer to two decimal places (e.g. 98.76). (c) n₁ = n2 = 1 . Round your answer to the nearest integer.arrow_forwardConsider the hypothesis test Ho: = 622 against H₁: 6 > 62. Suppose that the sample sizes are n₁ = 20 and n₂ = 8, and that = 4.5; s=2.3. Use a = 0.01. (a) Test the hypothesis. Round your answers to two decimal places (e.g. 98.76). The test statistic is fo = i The critical value is f = Conclusion: i the null hypothesis at a = 0.01. (b) Construct the confidence interval on 02/022 which can be used to test the hypothesis: (Round your answer to two decimal places (e.g. 98.76).) iarrow_forward2011 listing by carmax of the ages and prices of various corollas in a ceratin regionarrow_forward
- س 11/ أ . اذا كانت 1 + x) = 2 x 3 + 2 x 2 + x) هي متعددة حدود محسوبة باستخدام طريقة الفروقات المنتهية (finite differences) من جدول البيانات التالي للدالة (f(x . احسب قيمة . ( 2 درجة ) xi k=0 k=1 k=2 k=3 0 3 1 2 2 2 3 αarrow_forward1. Differentiate between discrete and continuous random variables, providing examples for each type. 2. Consider a discrete random variable representing the number of patients visiting a clinic each day. The probabilities for the number of visits are as follows: 0 visits: P(0) = 0.2 1 visit: P(1) = 0.3 2 visits: P(2) = 0.5 Using this information, calculate the expected value (mean) of the number of patient visits per day. Show all your workings clearly. Rubric to follow Definition of Random variables ( clearly and accurately differentiate between discrete and continuous random variables with appropriate examples for each) Identification of discrete random variable (correctly identifies "number of patient visits" as a discrete random variable and explains reasoning clearly.) Calculation of probabilities (uses the probabilities correctly in the calculation, showing all steps clearly and logically) Expected value calculation (calculate the expected value (mean)…arrow_forwardif the b coloumn of a z table disappeared what would be used to determine b column probabilitiesarrow_forward
- Construct a model of population flow between metropolitan and nonmetropolitan areas of a given country, given that their respective populations in 2015 were 263 million and 45 million. The probabilities are given by the following matrix. (from) (to) metro nonmetro 0.99 0.02 metro 0.01 0.98 nonmetro Predict the population distributions of metropolitan and nonmetropolitan areas for the years 2016 through 2020 (in millions, to four decimal places). (Let x, through x5 represent the years 2016 through 2020, respectively.) x₁ = x2 X3 261.27 46.73 11 259.59 48.41 11 257.96 50.04 11 256.39 51.61 11 tarrow_forwardIf the average price of a new one family home is $246,300 with a standard deviation of $15,000 find the minimum and maximum prices of the houses that a contractor will build to satisfy 88% of the market valuearrow_forward21. ANALYSIS OF LAST DIGITS Heights of statistics students were obtained by the author as part of an experiment conducted for class. The last digits of those heights are listed below. Construct a frequency distribution with 10 classes. Based on the distribution, do the heights appear to be reported or actually measured? Does there appear to be a gap in the frequencies and, if so, how might that gap be explained? What do you know about the accuracy of the results? 3 4 555 0 0 0 0 0 0 0 0 0 1 1 23 3 5 5 5 5 5 5 5 5 5 5 5 5 6 6 8 8 8 9arrow_forward
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