Introduction To Statistics And Data Analysis
6th Edition
ISBN: 9781337793612
Author: PECK, Roxy.
Publisher: Cengage Learning,
expand_more
expand_more
format_list_bulleted
Concept explainers
Videos
Textbook Question
thumb_up100%
Chapter 2.3, Problem 41E
In an experiment to compare two different surgical procedures for hernia repair (“A Single-Blinded, Randomized Comparison of Laparoscopic Versus Open Hernia Repair in Children,” Pediatrics [2009]: 332-336), 89 children were assigned at random to one of the two surgical methods. The researchers relied on the random assignment of subjects to treatments to create comparable groups with respect to extraneous variables that they did not control. One such extraneous variable was age.
After random assignment to treatments, the researchers looked at the age distribution of the children in each of the two experimental groups (laparoscopic repair [LR] and open repair ［OR]). The accompanying figure is similar to one in the paper.
Based on this figure, has the random assignment of subjects to experimental groups been successful in creating groups that are similar with respect to the ages of the children in the groups? Explain.
Expert Solution & Answer
Trending nowThis is a popular solution!
Students have asked these similar questions
A consumer advocacy group wanted to study whether different airline carriers differed in terms of their delayed flights. In particular, the researchers were interested in the relationship between p1, the proportion of Alpha Airlines flights that were delayed at least 15 minutes, and p2, the proportion of Beta Airlines flights that were delayed at least 15 minutes. A random sample of 1,000 Alpha flights and a separate random sample of 1,000 Beta flights found that 67 of the Alpha fights and 160 of the Beta flights were delayed at least 15 minutes. The conditions for inference were checked and verified.
Does this set of samples provide strong evidence that Alpha Airlines has a smaller proportion of flights that are delayed at least 15 minutes than Beta Airlines, at the α = 0.05 significance level?
Find the z-table here.
A. The test statistic is z = –6.56 and the P-value ≈ 0. Since the P-value ≈ 0 < 0.05, there is not sufficient evidence that Alpha Airlines has fewer delayed…
The article “The Effects of a Low-Fat, Plant-Based DietaryIntervention on Body Weight, Metabolism, and InsulinSensitivity in Postmenopausal Women” (Amer. J. of Med.,2005: 991–997) reported on the results of an experiment inwhich half of the individuals in a group of 64 postmenopausaloverweight women were randomly assigned to a particularvegan diet, and the other half received a diet based on NationalCholesterol Education Program guidelines. The sample meandecrease in body weight for those on the vegan diet was 5.8kg, and the sample SD was 3.2, whereas for those on the control diet, the sample mean weight loss and standard deviationwere 3.8 and 2.8, respectively. Does it appear the true averageweight loss for the vegan diet exceeds that for the control dietby more than 1 kg? Carry out an appropriate test of hypotheses at significance level .05 based on calculating a P-value
In a study of the effectiveness of a fabric device that acts like a support stocking for a weak or damaged heart, 110 people who consented to treatment were assigned at random to either a standard treatment consisting of drugs or the experimental treatment that consisted of drugs plus surgery to install the stocking. After two years, 30% of the 60 patients receiving the stocking had improved and 24% of the patients receiving the standard treatment had improved. (Use a statistical computer package to calculate the P-value. Use pexperimental − pstandard. Round your test statistic to two decimal places and your P-value to four decimal places.)
z
= ?
P
= ?
Chapter 2 Solutions
Introduction To Statistics And Data Analysis
Ch. 2.1 - The article How Dangerous Is a Day in the...Ch. 2.1 - The authors of the paper Fudging the Numbers:...Ch. 2.1 - The article Why We Fall for This (AARP Magazine,...Ch. 2.1 - The article Adolescents Living the 24/7 Lifestyle:...Ch. 2.1 - The article Acupuncture for Bad Backs: Even Sham...Ch. 2.1 - The article Display of Health Risk Behaviors on...Ch. 2.1 - The article Popping Cork Sound Makes Wine Taste...Ch. 2.1 - Fruit Juice May Be Fueling Pudgy Preschoolers,...Ch. 2.1 - The article Americans are Getting the Wrong Idea...Ch. 2.1 - Based on a survey conducted on the eDiets.com web...
Ch. 2.1 - A survey of adult Americans who are Internet users...Ch. 2.1 - Does sitting for long periods of time hurt your...Ch. 2.2 - A New York psychologist recommends that if you...Ch. 2.2 - As part of a curriculum review, a psychology...Ch. 2.2 - A petition with 500 signatures is submitted to a...Ch. 2.2 - The article Bicyclists and Other Cyclists (Annals...Ch. 2.2 - The article Teenage Physical Activity Reduces Risk...Ch. 2.2 - For each of the situations described, state...Ch. 2.2 - Of the 6500 students enrolled at a community...Ch. 2.2 - Briefly explain why it is advisable to avoid the...Ch. 2.2 - A sample of pages from this book is to be...Ch. 2.2 - The chairman of a California ballot initiative...Ch. 2.2 - The authors of the paper Digital Inequality:...Ch. 2.2 - The 2013 National Study of Substance Use Habits of...Ch. 2.2 - The paper Deception and Design: The Impact of...Ch. 2.2 - The authors of the paper Playing by the Rules:...Ch. 2.2 - Participants in a study of honesty in online...Ch. 2.2 - The article Credit Card Activity for College...Ch. 2.2 - The financial aid advisor of a university plans to...Ch. 2.2 - Suppose that you were asked to help design a...Ch. 2.2 - The article High Levels of Mercury Are Found in...Ch. 2.2 - Whether or not to continue a Mardi Gras Parade...Ch. 2.3 - The head of the quality control department at a...Ch. 2.3 - A study of college students showed a temporary...Ch. 2.3 - According to the article Rubbing Hands Together...Ch. 2.3 - The following is from an article titled After the...Ch. 2.3 - The report Comparative Study of Two Computer Mouse...Ch. 2.3 - The Institute of Psychiatry at Kings College...Ch. 2.3 - In an experiment to compare two different surgical...Ch. 2.3 - In many digital environments, users are allowed to...Ch. 2.3 - Does playing action video games provide more than...Ch. 2.3 - Construct a diagram to represent the note-taking...Ch. 2.3 - Construct a diagram to represent the gasoline...Ch. 2.3 - An advertisement for a sweatshirt that appeared in...Ch. 2.3 - The paper Turning to Learn: Screen Orientation and...Ch. 2.3 - Consider the study described in the previous...Ch. 2.3 - The Pew Research Center conducted a study of...Ch. 2.3 - Consider the study described in the previous...Ch. 2.3 - Red wine contains flavonol, an antioxidant thought...Ch. 2.4 - Explain why some studies include both a control...Ch. 2.4 - Explain why blinding is a reasonable strategy in...Ch. 2.4 - Give an example of an experiment for each of the...Ch. 2.4 - The article Study Points to Benefits of Knee...Ch. 2.4 - In an experiment to compare two different surgical...Ch. 2.4 - The article Placebos Are Getting More Effective....Ch. 2.4 - The article Yes That Miley Cyrus Biography Helps...Ch. 2.4 - Suppose that the researchers who carried out the...Ch. 2.4 - The article Doctor Dogs Diagnose Cancer by...Ch. 2.4 - Pismo Beach, California, has an annual clam...Ch. 2.4 - The San Luis Obispo Tribune (May 7, 2002) reported...Ch. 2.4 - The article A Debate in the Dentists Chair (San...Ch. 2.5 - The article Effects of Too Much TV Can Be Undone...Ch. 2.5 - Prob. 66ECh. 2 - A mortgage lender routinely places advertisements...Ch. 2 - The article Rethinking Calcium Supplements (US...Ch. 2 - A pollster for the Public Policy Institute of...Ch. 2 - A study in Florida is examining whether health...Ch. 2 - The press release Men Need to Man Up, According to...Ch. 2 - A news release from Intel Intels Security...Ch. 2 - USA TODAY (August 25, 2015) reported that American...Ch. 2 - The paper Effect of a Nutritional Supplement on...Ch. 2 - A manufacturer of clay roofing tiles would like to...Ch. 2 - A tropical forest survey conducted by Conservation...
Additional Math Textbook Solutions
Find more solutions based on key concepts
z Scores. In Exercises 5-8, express all z scores with two decimal places.
8. Plastic Waste Data Set 31 “Garbage...
Elementary Statistics Using Excel (6th Edition)
AVX Home Entertainment, Inc., recently began a “no-hassles” return policy. A sample of 500 customers who recent...
EBK STATISTICAL TECHNIQUES IN BUSINESS
A Pew Research Center survey found a noticeable rise in smartphone ownership and internet usage in emerging and...
Business Statistics: A First Course (8th Edition)
(a) Make a stem-and-leaf plot for these 24 observations on the number of customers who used a down-town CitiBan...
Applied Statistics in Business and Economics
Fill in the blank: The probability that a fair coin lands heads is 0.5. Therefore, we can be sure that if we to...
Elementary Statistics ( 3rd International Edition ) Isbn:9781260092561
c
Solve.
70. Copy Center Account. Rachel’s copy-center bill for July was $327. She made a payment of $200 and t...
Developmental Mathematics (9th Edition)
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, statistics and related others by exploring similar questions and additional content below.Similar questions
- In randomized, double-blind clinical trials of a new vaccine, children were randomly divided into two groups. Subjects in group 1 received the new vaccine while subjects in group 2 received a control vaccine. After the second dose, 116 of 651 subjects in the experimental group (group 1) experienced fever as a side effect. After the second dose, 73 of 532 of the subjects in the control group (group 2) experienced fever as a side effect. Does the evidence suggest that a higher proportion of subjects in group 1 experienced fever as a side effect than subjects in group 2 at the α=0.10 level of significance? #1 Find the test statistic for this hypothesis test.arrow_forwardElizon Pharmaceuticals, Inc., announced the results of its first human trial of NPI 32101, a topical form of its skin ointment. A total of 225 patients diagnosed with skin irritations were randomly divided into three groups as part of a double-blind, placebo-controlled study to test the effectiveness of the new topical cream. The first group received a 0.5% cream, the second group received a 1.0% cream, and the third group received a placebo. Groups were treated twice daily for a 6-week period. (a)What type of experimental design is this? (b)What is the control group for this study? (c)What is the factor that is set to predetermined levels? What is the treatment? (d)What does it mean for this study to be double-blind? (e)Identify the experimental units. (f)Draw a diagram to illustrate the design.arrow_forwardAn article from the American Journal of Public Health reports the results from a randomized study designed to evaluate the efficacy of an intervention targeted to Hispanic/Latino men who identify as gay, bi-sexual or other men who have sex with men (MSM). A representative sample of 254 such men was randomized to be in either the intervention group (n=152, with 141 ultimately participating in the study) or the control group (n=152, with 147 ulitmately participating in the study). The primary outcome under study getting tested for HIV within the six-months following group assignment (randomization) among those who had been sexually active in this same six-month follow-up period. At six months of follow-up, 141 subjects in the intervention group reported having had sex (with men and/or women) since randomization. Of these 141 men, 114 had been tested for HIV since being randomized. At six months of follow-up, 147 subjects in the control group reported having had sex (with men…arrow_forward
- A study of “adverse symptoms” in users of over-the-counter pain relief medications assigned subjects at random toone of two common pain relievers: acetaminophen and ibuprofen. In all, 650 subjects took acetaminophen, and 44experienced some adverse symptom. Of the 347 subjects who took ibuprofen, 49 had an adverse symptom. Is thisconvincing evidence that the two pain relievers differ in the proportion of people who experience an adverse symptom?arrow_forwardIn its January 25, 2012, issue, the Journal of the American Medical Association reported on the effects of overconsumption of low, normal, and high protein diets on weight gain, energy expenditure, and body composition. Researchers conducted a single blind, randomized controlled trial of 25 U.S. adults. The subjects were healthy, weight-stable, male and female volunteers, aged 18 to 35 years. All subjects consumed a weight-stabilizing diet for 13 to 25 days. Afterwards, the researchers randomly assigned participants to diets containing various percentages of energy from protein: 5% (low protein), 15% (normal protein), or 25% (high protein). The subjects were not aware of the specific protein level diet to which they were assigned. On these diets the researchers overfed the participants during the last 8 weeks of their 10 to 12 week stay in the inpatient metabolic unit. The goal was to investigate the effect of overconsumption of protein on weight gain, energy expenditure, and body…arrow_forwardIn a randomized double-blind clinical trials of a new vaccine children were randomly divided into two groups subjects in group one received the new vaccine while subjects in group 2 received a control vaccine after the second dose 112 of 690 subjects in the experimental group 1 experienced drowsiness as a side effect after the second dose 69 of 571 of the subjects in the control group 2 experienced drowsiness as a side effect does the evidence suggest that a higher proportion of subjects in group 1 experience drowsiness as a side effect than subjects in group 2 at 0.05 level of significance? Determine the null and alternative hypothesis? find the test statistic for this hypothesis test? determine the P value for this hypothesis test? do we reject or not reject the null hypothesis and why? State your conclusion?arrow_forward
- In randomized, double-blind clinical trials of a new vaccine, infants were randomly divided into two groups. Subjects in group 1 received the new vaccine while subjects in group 2 received a control vaccine. After the second dose, 126 of 387 subjects in the experimental group (group 1) experienced drowsiness as a side effect. After the second dose, 158 of 574 of the subjects in the control group (group 2) experienced drowsiness as a side effect. Does the evidence suggest that a higher proportion of subjects in group 1 experienced drowsiness as a side effect than subjects in group 2 at the α=0.01 level of significance? Verify the model requirements. Select all that apply. A. The sample size is less than 5% of the population size for each sample. B. n1p11−p1≥10 and n2p21−p2≥10 C. The samples are dependent. D. The sample size is more than 5% of the population size for each sample. E. The samples are independent. F. The data come…arrow_forwardA random sample of 50 suspension helmets used by motorcycle riders and automobile race-car drivers was subjected to an impact test, and on 18 of these helmets some damage was observed.arrow_forwardIn a study of the effectiveness of a new device that supports a weak or damaged heart, 150 people who consented to treatment were assigned at random to either a standard treatment consisting of drugs or the experimental treatment that consisted of drugs and surgery to install the new device. After two years, 60% of the 67 patients who received the device had improved and 40% of the patients who received the standard treatment had improved. Does this data provide convincing evidence that the proportion of patients who recieved the experimental treatment who improved is higher than for the patients who received the standard treatment? Test the relevant hypotheses using a significance level of 0.05. (Use pexperimental − pstandard ).A) State the null and alternative hypotheses. H0: pe − ps = 0, HA: pe − ps ≠ 0 H0: pe − ps = 0, HA: pe − ps < 0 H0: pe − ps = 0, HA: pe − ps > 0 B) Find the test statistic.z = C) What is the p-value?P-Value = D) State your conclusion in terms of…arrow_forward
- A study published in 2007 by Christopher Johnson, professor of music education and music therapy at the University of Kansas, revealed that students in elementary schools who took private music lessons scored around 20 percent higher in math scores on standardized tests, compared to students who did not take private music lessons. Is this a randomized experiment or an observational study? a) Randomized experiment, since researchers gave students standardized tests. b) Observational study, since whether the student took private music lessons was not randomly assigned. c) Observational study, since math scores were not randomly assigned. d) Observational study, since this was not a random sample.arrow_forwardThe article “Capillary Leak Syndrome in Children with C4A-Deficiency Undergoing Cardiac Surgery with Cardiopulmonary Bypass: A Double-Blind, Randomised Controlled Study” (S. Zhang, S. Wang, et al., Lancet, 2005:556–562) presents the results of a study of the effectiveness of giving blood plasma containing complement component C4A to pediatric cardiopulmonary bypass patients. Of 58 patients receiving C4A-rich plasma, the average length of hospital stay was 8.5 days and the standard deviation was 1.9 days. Of 58 patients receiving C4A-free plasma, the average length of hospital stay was 11.9 days and the standard deviation was 3.6 days. Can you conclude that the mean hospital stay is shorter for patients receiving C4A-rich plasma?arrow_forwardAnother experiment involving processor speed (Sp) and size of random access memory (RAM) for computers produced the following data Sp1 Sp2 RAM 1 48 37 38 35 37 39 RAM 2 30 35 31 22 26 30 Are the factors Sp and RAM or their interaction statistically significant?arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
MATLAB: An Introduction with ApplicationsStatisticsISBN:9781119256830Author:Amos GilatPublisher:John Wiley & Sons Inc
Probability and Statistics for Engineering and th...StatisticsISBN:9781305251809Author:Jay L. DevorePublisher:Cengage Learning
Statistics for The Behavioral Sciences (MindTap C...StatisticsISBN:9781305504912Author:Frederick J Gravetter, Larry B. WallnauPublisher:Cengage Learning
Elementary Statistics: Picturing the World (7th E...StatisticsISBN:9780134683416Author:Ron Larson, Betsy FarberPublisher:PEARSON
The Basic Practice of StatisticsStatisticsISBN:9781319042578Author:David S. Moore, William I. Notz, Michael A. FlignerPublisher:W. H. Freeman
Introduction to the Practice of StatisticsStatisticsISBN:9781319013387Author:David S. Moore, George P. McCabe, Bruce A. CraigPublisher:W. H. Freeman
MATLAB: An Introduction with Applications
Statistics
ISBN:9781119256830
Author:Amos Gilat
Publisher:John Wiley & Sons Inc
Probability and Statistics for Engineering and th...
Statistics
ISBN:9781305251809
Author:Jay L. Devore
Publisher:Cengage Learning
Statistics for The Behavioral Sciences (MindTap C...
Statistics
ISBN:9781305504912
Author:Frederick J Gravetter, Larry B. Wallnau
Publisher:Cengage Learning
Elementary Statistics: Picturing the World (7th E...
Statistics
ISBN:9780134683416
Author:Ron Larson, Betsy Farber
Publisher:PEARSON
The Basic Practice of Statistics
Statistics
ISBN:9781319042578
Author:David S. Moore, William I. Notz, Michael A. Fligner
Publisher:W. H. Freeman
Introduction to the Practice of Statistics
Statistics
ISBN:9781319013387
Author:David S. Moore, George P. McCabe, Bruce A. Craig
Publisher:W. H. Freeman
Continuous Probability Distributions - Basic Introduction; Author: The Organic Chemistry Tutor;https://www.youtube.com/watch?v=QxqxdQ_g2uw;License: Standard YouTube License, CC-BY
Probability Density Function (p.d.f.) Finding k (Part 1) | ExamSolutions; Author: ExamSolutions;https://www.youtube.com/watch?v=RsuS2ehsTDM;License: Standard YouTube License, CC-BY
Find the value of k so that the Function is a Probability Density Function; Author: The Math Sorcerer;https://www.youtube.com/watch?v=QqoCZWrVnbA;License: Standard Youtube License