An industrial/organizational psychologist has been consulting with a company tha
ID: 3338887 • Letter: A
Question
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 18 months after the workshop, a sample of 36 job seekers who received training on using the Internet to find job listings scored an average of 7.3 as measured on a 9-point job-search motivation scale, with a standard deviation of 1.5. The typical job seeker scores 6.1 points. The psychologist finds that the estimated Cohen's d is 0.800the t statistic is 4.80, and r2 is 0.397 Using Cohen's d and Cohen's guidelines for interpreting the effect size with the estimated Cohen's d, there is a large treatment effect. Using r2 and the extension of Cohen's guidelines for interpreting the effect size using r2, there is a medium 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.) Another one of the psychologist's findings is that a sample of 121 job seekers who received training on interview skills worked an average of 6.1 hours per week, with a standard deviation of 1.2. The typical job seeker works 5.7 hours , the t statistic is 3.64, and r2 is She finds that the estimated Cohen's d is 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 with r2, there is a Using Cohen's d treatment effect.Explanation / Answer
Cohen's d = x - u / s
= 5.7-6.1/1.5
= 0.267
r2 = 0.100
since t = r* sqrt(n - 2) / sqrt(1 - r2)
3.64 = r * sqrt(119) / sqrt(1 - r2)
r = 0.100
Using cohen's d, there is large treatment effect
Using r2, there is medium treatment effect