Stressed-Out Bus Drivers. Frustrated passengers, congested streets, time schedules, and air and noise pollution are just some of the physical and social pressures that lead many urban bus drivers to retire prematurely with disabilities such as coronary heart disease and stomach disorders. An intervention program designed by the Stockholm Transit District was implemented to improve the work conditions of the city’s bus drivers. Improvements were evaluated by G. Evans et al., who collected physiological and psychological data for bus drivers who drove on the improved routes (intervention) and for drivers who were assigned the normal routes (control). Their findings were published in the article “Hassles on the Job: A Study of a Job Intervention With Urban Bus Drivers” (Journal of Organizational Behavior, Vol. 20, pp. 199–208). Following are data, based on the results of the study, for the heart rates, in beats per minute, of the intervention and control drivers.
- a. Obtain dotplots for each of the two data sets, using the same scales.
- b. Use your result from part (a) to compare the two data sets.
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Chapter 2 Solutions
Introductory Statistics (10th Edition)
- Individuals with strong religious beliefs often turn to their faith to cope with stressful life events. Relying on God's love and caring is referred to as positive religious coping. Andrea Phelps and her colleagues studied the relationship between positive religious coping and the type of care received by terminally ill cancer patients. Most of the patients in the study were Christian. [Source: Phelps, A. et al., "Religious coping and use of intensive life-prolonging care near death in patients with advanced cancer." Journal of the American Medical Association, 301 (2009): 1140-1147.] Suppose another researcher conducts a similar study but uses a sample of patients whose religious traditions are more varied than the patients in the Phelps study. He samples 400 terminally ill patients to see whether their practicing a religion is related to how likely they are to seek intensive life-prolonging care. The following table shows the results of the study. Observed Frequencies Seeks Intensive…arrow_forwardDr. Farah is an educational psychologist who is interested in studying the potential causal relationship between doing homework and academic achievement. In January, Dr. Farah has her students report their fall GPA (a measure of academic achievement) and estimate how many hours they spent doing homework during a typical week in the fall semester. In May, Dr. Farah measures the same variables again (the estimated number of hours spent doing homework during a typical week in the spring semester and their spring GPA). She finds the following correlations. Imagine that Dr. Farah noted a cyclical, reinforcing relationship between homework and academic achievement. For this to be case, which of the following correlations would need to be significant? a. Correlations 1 and 6 b. Correlations 2 and 5 c. Correlations 3 and 4 d. Correlations 2 and 3 Answer is C for this question. Why this one is the answer and others are not?arrow_forwardAs an admissions counselor, I am interested in understanding whether or not there is a difference in stress levels not only between different majors but also between different classes (Freshman v. Seniors). I gather the following data from students from three majors (Psychology, Chemistry, and Engineering), that are in their freshmen or senior years and ask them about their stress levels (scale of 1-10, with lower numbers meaning less stress). Using the data below, test whether there are effects of class, major, or an interaction between them at an alpha of 0.05. Psychology Chemistry Engineering Freshmen 3, 4, 4, 2, 4 4, 5, 7, 8, 4 5, 7, 7, 8, 5 Senior 4, 5, 5, 3, 5 8, 5, 6, 7, 7 9, 9, 8, 7, 9 Complete the ANOVA summary table below: Source SS df MS (variance) F MAJOR CLASS MAJOR*CLASS ERROR/RESIDUAL Nothing here TOTAL Nothing here Nothing here What can we conclude?…arrow_forward
- As an admissions counselor, I am interested in understanding whether or not there is a difference in stress levels not only between different majors but also between different classes (Freshman v. Seniors). I gather the following data from students from three majors (Psychology, Chemistry, and Engineering), that are in their freshmen or senior years and ask them about their stress levels (scale of 1-10, with lower numbers meaning less stress). Using the data below, test whether there are effects of class, major, or an interaction between them at an alpha of 0.05. Psychology Chemistry Engineering Freshmen 3, 4, 4, 2, 4 4, 5, 7, 8, 4 5, 7, 7, 8, 5 Senior 4, 5, 5, 3, 5 8, 5, 6, 7, 7 9, 9, 8, 7, 9 What is the critical F value for major? ___________ What is the critical F value for class? ___________ What is the critical F value for the interaction between major and class? ___________arrow_forwardRead the scenario below to determine which one of the time threats to internal validity (test reactivity, instrumentation, history, and maturation) is of most concern, and provide one way to control for the threat. A researcher examines students' perception of their body image by conducting a 2-year longitudinal study of middle-school students (grades 6 - 8). Body image is measured using a scale and the same scale is measured under the same conditions at the beginning and end of the study.arrow_forwardDoes posting calorie content for menu items affect people’s choices in fast-food restaurants? According to results obtained by Elbel, Gyamfi, and Kersh (2011), the answer is no. The researchers monitored the calorie content of food purchases for children and adolescents in four large fast-food chains before and after mandatory labeling began in New York City. Although most of the adolescents reported noticing the calorie labels, apparently the labels had no effect on their choices. Data similar to the results obtained show an average of M =786 per meal with s = 85 for n =100 children and adolescents before the labeling, compared to an average M = 772of with s =91 for a similar sample of n = 100 after the mandatory posting. Use a two-tailed test with alpha = .05 to determine whether the mean number of calories after the posting is significantly different than before calorie content was posted.arrow_forward
- Does posting calorie content for menu items affect people’s choices in fast food restaurants? According to results obtained by Elbel, Gyamfi, and Kersh (2011), the answer is no. The researchers monitored the calorie content of food purchases for children and adolescents in four large fast food chains before and after mandatory labeling began in New York City. Although most of the adolescents reported noticing the calorie labels, apparently the labels had no effect on their choices. Data similar to the results obtained show an average of M = 786 calories per meal with s = 85 for n = 100 children and adolescents before the labeling, compared to an average of M = 772 calories with s = 91 for a similar sample of n = 100 after the mandatory posting. Use a two-tailed test with α = .05 to determine whether the mean number of calories after the posting is significantly different than before calorie content was posted. Calculate r2 to measure effect size for the mean difference.arrow_forwardThe effect of aid is a subject of considerable academic and policy interest. In this question we examine the relationship between foreign aid and civil conflict using a recent paper by Crost et al. (2014) in the Philippines. The authors collect data on civil conflict related incidents at the municipality level as well as information on aid receipts at the municipality level. The conflict data was collected from the Philippine military and provides casualty counts (as well as the party responsible) by municipality. Aid in this context refers to a large anti-poverty program (the KALAHI-CIDSS) funded by the World Bank and run from 2003-2008. The program provided cash grants to municipalities to build infrastructure such as roads, water-systems, clinics and schools. The grants were fairly large and accounted for approximately 15% of the annual budget for the average municipality. (a) Let Yi denote the number of conflict casualties in municipality i in a given timeperiod after the…arrow_forward"Bullying." according to noted expert Dan Olweus, "poisons the educational environment and affects the learning of every child." Bullying and victimization are evident as early as preschool, with the problem peaking in middle school. Suppose you are interested in the emotional well-being of not only the victims but also bystanders, bullies, and those who bully but who are also victims (bully-victims). You decide to measure depression in a group of victims and a group of bully-victims using a 26-item, 3-point depression scale. Assume scores on the depression scale are normally distributed and that the variances of the depression scores are the same among victims and bully-victims. The group of 25 victims scored an average of 25.3 with a sample standard deviation of 9 on the depression scale. The group of 23 bully-victims scored an average of 20.5 with a sample standard deviation of 8 on the same scale. You do not have any presupposed assumptions about whether victims or bully-victims…arrow_forward
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