An industrial/organizational psychologist has been consulting with a company that runs weekend job-seeking workshops for the unemployed. She collected data on several issues related to these workshops and, after conducting statistical tests, obtained statistically significant findings. She needs to find a way to evaluate effect size so that she can make recommendations to the company. One of the psychologist’s findings is that immediately after the workshop, a sample of 81 job seekers who received training on using the Internet to find job listings worked more than 30 hours per week an average of 8.7 months in the last year, with a standard deviation of 4.1. The typical job seeker works 7.4 months. The psychologist finds that the estimated Cohen’s d is    , the t statistic is 2.83, and r² is    .   Using Cohen’s d and Cohen’s guidelines for interpreting the effect size with the estimated Cohen’s d, there is a    treatment effect. Using r² and the extension of Cohen’s guidelines for interpreting the effect size using r², there is a    treatment effect. (Hint: When using Cohen’s guidelines for interpreting the effect size, if the value lies between two categories, then specify the range covered by both categories, for example, medium to large.)

Researchers asked soda drinkers to view either the logo for their favorite soda or a graphic warning demonstrating the harmful effects of sugary beverages (e.g., tooth decay, obesity) and then measured their negative mood with a short survey. They found that those participants who saw the warnings reported significantly greater negative moods than those who saw the logos. Which statistical test should be used?

In recent years there has been considerable controversy over the use of standardized testing of high school students. Supporters say that the practice is a good measure of both student progress and teacher performance. Opponents say that too much testing impedes learning and causes unnecessarily large expenses for the school districts. There are even reports that a significant number of high school students opt out of taking some of the standardized tests. In one large city where the school district reported that the average score on a national test taken by students in their junior year was 74, a large group of parents felt that this average was too low. The parents contracted a research company in an attempt to show that the average score was higher than the claimed average of 74. The research company took a random sample of 100 juniors and they collected the corresponding 100 exam scores for those students. - what hypotheses is most appropriate to deal with the problem above. - What…

The Wall Street Journal asked Concur Technologies, Inc., an expense management company, to examine data from 8.3 million expense reports to provide insights regarding business travel expenses. Their analysis of the data showed that New York was the most expensive city. The following table shows the average daily hotel room rate (*) and the average amount spent on entertainment (y) for a random sample of 9 of the 25 most-visited U.S. cities. These data lead to the estimated regression equation ŷ = 17.49 +1.0334x. For these data SSE = 1541.4. Click on the datafile logo to reference the data. Use Table 1 of Appendix B. DATA file City Boston Denver Nashville New Orleans Phoenix San Diego San Francisco San Jose Room Rate ($) 148 96 91 110 90 102 136 90 82 Tampa a. Predict the amount spent on entertainment for a particular city that has a daily room rate of $89 (to 2 decimals). $ Entertainment ($) 161 105 101 142 ***** b. Develop a 95% confidence interval for the mean amount spent on…

A researcher conducts a cross-sectional analysis of workers and finds a positive correlation between the number of hours high schoolers spent practicing a musical instrument and their subsequent college performance. Explain how this relationship could be causal. The researcher advocates a policy of requiring all students to take band in order to improve future outcomes. What is a possible problem with this analysis?

In recent years there has been considerable controversy over the use of standardized testing of high school students. Supporters say that the practice is a good measure of both student progress and teacher performance. Opponents say that too much testing impedes learning and causes unnecessarily large expenses for the school districts. There are even reports that a significant number of high school students opt out of taking some of the standardized tests. In one large city where the school district reported that the average score on a national test taken by students in their junior year was 74, a large group of parents felt that this average was too low. The parents contracted a research company in an attempt to show that the average score was higher than the claimed average of 74. The research company took a random sample of 100 juniors and they collected the corresponding 100 exam scores for those students. 15. Pick the hypotheses most appropriate to deal with the problem above. a)…

Because statistical software plays such an important role in modern statistical applications, many studies have encouraged the use of technology in statistics courses. The Guidelines for the Assessment and Instruction in Statistics Education (GAISE) (Aliaga et al., 2005) project was funded by the American Statistical Association to examine needs for college level statistics courses. One of the six recommendations from GAISE is the use of technology for developing conceptual understanding and analyzing data. A survey was sent to students at 100 different universities across the United States to access the relationship between ease of learning the statistical software program SAS and a student's currently level of SAS proficiency. The results of the survey are published in Jackson et al., 2011, in the International Mathematical Forum journal and are shown below. Table 1.Two-way table for ease of learning SAS and SAS proficiency level. Proficiency Not Somewhat Total Very proficient…

A team of epidemiologists at the Mayo Clinic wanted to find whether there is an association between obesity and cardiovascular disease (CVD). They conducted a prospective cohort study following obese and non-obese individuals who were free of CVD at the beginning of study for five years. The investigators were also interested in assessing age as a potential confounder, effect modifier, or both. Use the data below to answer the accompanying questions.     CVD No CVD Total Obese 10 90 100 Not Obese 35 465 500 Total 45 555 600       CVD No CVD Total Obese 36 164 200 Not Obese 25 175 200 Total 61 339 400   1. Compute the appropriate measure of association for those who were less than age 50.  2. Compute the appropriate measure of association for those who were older or equal to age 50.  3. Compute the crude measure of association?  4. List three attributes that age must satisfy before it could…