Statistics: The Art and Science of Learning from Data (4th Edition)
4th Edition
ISBN: 9780321997838
Author: Alan Agresti, Christine A. Franklin, Bernhard Klingenberg
Publisher: PEARSON
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Chapter 11, Problem 50CP
a.
To determine
Identify the response variable and the explanatory variable and their categories for 2×2
b.
To determine
Explain the interpretation of parenthetical part of the quoted sentence to a non-statistical person.
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Chapter 11 Solutions
Statistics: The Art and Science of Learning from Data (4th Edition)
Ch. 11.1 - Gender gap in politics? In the United States, is...Ch. 11.1 - Prob. 2PBCh. 11.1 - Williams College admission Data from 2013 posted...Ch. 11.1 - Prob. 4PBCh. 11.1 - Marital happiness and income In the GSS, subjects...Ch. 11.1 - What is independent of happiness? Which one of the...Ch. 11.1 - Sample evidence about independence Refer to the...Ch. 11.2 - Life after death and gender In the 2012 GSS, 605...Ch. 11.2 - Happiness and gender For the 2 3 table on gender...Ch. 11.2 - Prob. 10PB
Ch. 11.2 - Marital happiness and income In Exercise 11.5 when...Ch. 11.2 - First and second free throw independent? In pro...Ch. 11.2 - Cigarettes and marijuana The table on the...Ch. 11.2 - Prob. 14PBCh. 11.2 - Help the environment In 2010 the GSS asked whether...Ch. 11.2 - Prob. 16PBCh. 11.2 - Aspirin and heart attacks A Swedish study used...Ch. 11.2 - z test for heart attack study Refer to the...Ch. 11.2 - Severity of fever after flu shot The study...Ch. 11.2 - Prob. 20PBCh. 11.2 - Testing a genetic theory In an experiment on...Ch. 11.2 - Birthdays by quarters Based on a random sample of...Ch. 11.2 - Checking a roulette wheel Karl Pearson devised the...Ch. 11.3 - Democrat, race, and gender The two tables show...Ch. 11.3 - Death penalty associations Table 11.10, summarized...Ch. 11.3 - Smoking and alcohol The table refers to a survey...Ch. 11.3 - Sex of victim and offender For murders in the...Ch. 11.3 - Smelling and mortality A recent study (Pinto et...Ch. 11.3 - Vioxx In September 2004, the pharmaceutical...Ch. 11.3 - Egg and cell derived vaccine When comparing the...Ch. 11.3 - Risk of dying for teenagers According to...Ch. 11.3 - Marital happiness The table shows 2012 GSS data on...Ch. 11.3 - Party ID and gender The table shows the 2012 GSS...Ch. 11.3 - Chi-squared versus measuring association For the...Ch. 11.4 - Standardized residuals for happiness and income...Ch. 11.4 - Prob. 36PBCh. 11.4 - Prob. 37PBCh. 11.4 - Prob. 38PBCh. 11.4 - Prob. 39PBCh. 11.4 - Prob. 40PBCh. 11.5 - Keeping old dogs mentally sharp In an experiment...Ch. 11.5 - Prob. 43PBCh. 11.5 - Prob. 44PBCh. 11.5 - Prob. 46PBCh. 11 - Female for president? When recent General Social...Ch. 11 - Prob. 48CPCh. 11 - Down and chi-squared For the data in the previous...Ch. 11 - Prob. 50CPCh. 11 - Prob. 51CPCh. 11 - Prob. 52CPCh. 11 - Prob. 53CPCh. 11 - Prob. 54CPCh. 11 - Prob. 55CPCh. 11 - Prob. 56CPCh. 11 - Seat belt helps? The table refers to passengers in...Ch. 11 - Prob. 58CPCh. 11 - Prob. 59CPCh. 11 - Prob. 60CPCh. 11 - Prob. 61CPCh. 11 - Prob. 62CPCh. 11 - Prob. 63CPCh. 11 - Prob. 64CPCh. 11 - Clarity of diamonds Does the clarity of a diamond...Ch. 11 - Benfords Law When looking at a collection of...Ch. 11 - Prob. 67CPCh. 11 - Prob. 68CPCh. 11 - Prob. 70CPCh. 11 - Prob. 71CPCh. 11 - Prob. 72CPCh. 11 - Prob. 73CPCh. 11 - Prob. 74CPCh. 11 - Prob. 75CPCh. 11 - Prob. 76CPCh. 11 - Prob. 77CPCh. 11 - Prob. 78CPCh. 11 - Prob. 79CPCh. 11 - Statistical versus practical significance In any...Ch. 11 - Prob. 81CPCh. 11 - Multiple response variables Each subject in a...Ch. 11 - Standardized residuals for 2 2 tables The table...Ch. 11 - Prob. 84CPCh. 11 - Prob. 85CPCh. 11 - Prob. 86CPCh. 11 - Prob. 87CPCh. 11 - Prob. 88CPCh. 11 - Voting with 16 A recent survey of Austrian high...
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- What is meant by the sample space of an experiment?arrow_forwardList the sample space of each experiment. Tossing three coinsarrow_forwardAs men age, their testosterone levels gradually decrease. This may cause a reduction in energy, an increase in fat, and other undesirable changes. Do testosterone supplements reverse some of these effects? A study in the Netherlands assigned 237 men aged 60 to 80 with low or low-normal testosterone levels to either a testosterone supplement or a placebo. Why is it necessary to include a control group in this experiment? Every experiment needs a control group in order to make proper comparisons between treatments. A control group is necessary to balance the effects of other variables among the treatment groups. A control group is necessary so any differences in the effects of the treatments can be distinguished from chance differences between the groups. A control group helps avoid confounding and reduces variability in the response variable. A control group is used to provide a baseline for comparing the effects of other treatments.arrow_forward
- A medical journal reported on an experiment intended to see if a certain drug could be used as a treatment for the eating disorder anorexia nervosa. The subjects were randomly divided into two groups. Of the 98 who received this drug, 70 were deemed healthy a year later, compared to 50 of the 88 who got the placebo. What is the population for this study? Is this an experimental study? Explain. What is the explanatory variable? What is the response variable? Complete the 2x2 table of counts.arrow_forwardOne study of cell phones and the risk of brain cancer looked at a group of 469 people who have brain cancer. The investigators then asked about the use of cell phones. Result: “Our data suggest that the use of hand- held cellular phones is not associated with risk of brain cancer. B . Based on this study, can you determine that cellular use does not CAUSE brain cancer? Why or why not?arrow_forwardQ1: Placebo effect of exercise In a high-profile research study, Crum and Langer (2007) performed an experiment to test whether the relationship between physical exercise and health is impacted by one's mindset: in other words, if there is any "placebo effect" of exercise. A sample of 84 randomly selected hotel workers in the United States were placed either into a treatment group (n=44) or control group (n=40) depending on which hotel they worked at. The treatment group was given information demonstrating how their work is good physical exercise, while the control group was not given this information. They measured the body mass index (BMI) for each worker before the experiment and again four weeks after the experiment. a. Are the treatment group and control group independent of each other, and if so why? b. Now consider the treatment group alone: are the measurements of BMI taken before and after the experiment independent of each other, and if so why? c. What is the most appropriate…arrow_forward
- A study was undertaken to investigate the effectiveness of an aquarobic exercise program for patients with osteoarthritis. A convenience sample of 70 individuals with arthritis was selected, and each person was randomly assigned to one of two groups. The first group participated in a weekly aquarobic exercise program for 8 weeks; the second group served as a control. Several pieces of data were collected from the individuals, including their total cholesterol (mg). Determine if there is a significant difference in the mean cholesterol for the two groups (aquarobic & control) at the start of the study using a significance level of 0.10. Difference Sample Diff. Std. Error df Aquarobic - Control 2.698 7.3227 65.6844 • What hypotheses should be tested? Make sure to select the hypotheses which are written with notation consistent with the type of samples selected. H.: µd = l2 H.: µ1 = µ2 H.:µd H.: Hd > 0 Ha: H1 # H2 Ha:µ1 > µ2 Ha:Hd < 0 Ha:H1 < µs Ha: Hd # 0 = 0 H,:µ1 0 H.: µ1 = µ2 H.: µd •…arrow_forwardA study was undertaken to investigate the effectiveness of an aquarobic exercise program for patients with osteoarthritis. A convenience sample of 70 individuals with arthritis was selected, and each person was randomly assigned to one of two groups. The first group participated in a weekly aquarobic exercise program for 8 weeks; the second group served as a control. Several pieces of data were collected from the individuals, including their total cholesterol (mg). Determine if there is a significant difference in the mean cholesterol for the two groups (aquarobic & control) at the start of the study using a significance level of 0.01. Difference Sample Diff. Std. Error df Aquarobic - Control -13.9045 6.8214 67.8635 What hypotheses should be tested? Make sure to select the hypotheses which are written with notation consistent with the type of samples selected. Ho:μd=0Ho:μd=0Ha:μd>0Ha:μd>0 Ho:μd=0Ho:μd=0Ha:μd<0Ha:μd<0 Ho:μ1=μ2Ho:μ1=μ2Ha:μ1<μ2Ha:μ1<μ2…arrow_forwardDark Chocolate for Good Health A study¹ examines chocolate's effects on blood vessel function in healthy people. In the randomized, double-blind, placebo-controlled study, 11 people received 46 grams (1.6 ounces) of dark chocolate (which is naturally flavonoid-rich) every day for two weeks, while a control group of 10 people received a placebo consisting of dark chocolate with low flavonoid content. Participants had their vascular health measured (by means of flow-mediated dilation) before and after the two-week study. The increase over the two-week period was measured, with larger numbers indicating greater vascular health. For the group getting the good dark chocolate, the mean increase was 1.3 with a standard deviation of 2.32, while the control group had a mean change of -0.96 with a standard deviation of 1.58. ¹Engler, M., et. al., "Flavonoid-rich dark chocolate improves endothelial function and increases plasma epicatechin concentrations in healthy adults," Journal of the…arrow_forward
- A randomized, double-blind, placebo-controlled study evaluated the effect of the herbal remedy Echinacea purpurea in treating upper respiratory tract infections in 2- to 11-year olds. Each time a child had an upper respiratory tract infection, treatment with either echinacea or a placebo was given for the duration of the illness. One of the outcomes studied was “severity of symptoms.” A severity scale based on four symptoms was monitored and recorded by the parents of subjects for each instance of upper respiratory infection. The peak severity of symptoms in the 337 cases treated with echinacea had a mean score of 6.0 (standard deviation 2.3). The peak severity of symptoms in the placebo group (np = 370) had a mean score of 6.1 (standard deviation 2.4). Test the mean difference for significance using an independent t-test. Discuss your findingsarrow_forwardState the hypotheses for each of the three separate tests included in the two-factor ANOVA.arrow_forwardResearchers studying the effect of antibiotic treatment compared to symptomatic treatment for acute sinusitis randomly assigned 166 adults diagnosed with sinusitis into two groups. Participants in the antibiotic group received a 10-day course of an antibiotic, and the rest received symptomatic treatments as a placebo. These pills had the same taste and packaging as the antibiotic. At the end of the 10-day period patients were asked if they experienced improvement in symptoms since the beginning of the study. The distribution of responses is summarized below. Antibiotic Placebo Total Yes 72 60 132 No 13 21 31 Total 85 81 166 A simulation was conducted under the assumpton that the proportion of self-reported improvement with the antibiotic treatment is equal to the proportion of self-reported improvement with the palcebo. 100,000 simulated differences were generated to construct the null distribution shown. The value ˆpa,∼p^a,∼ represents the proportion of self-reported…arrow_forward
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