A study was recently approved to investigate the effects of Ritalin on children diagnosed with Attention-Deficit Hyperactivity Disorder (ADHD). A between-subjects design experiment was conducted in...

A study was recently approved to investigate the effects of Ritalin on children diagnosed with Attention-Deficit Hyperactivity Disorder (ADHD). A between-subjects design experiment was conducted in which 20 ten year-old adolescent males were randomly selected to serve as participants. All of the participants had been diagnosed with ADHD and had never received any form of intervention for their disorder. Each participant was randomly assigned to one of two groups. The 10 participants in Group 1 did not receive any medication during the one-year study. However, the remaining 10 participants in Group 2 received a daily oral administration of Ritalin for one year. During the one-year study period, the research staff monitored the academic progress of each participant and rated their progress on an Attention Deficit Scale that provided an index of attention on a 0 to 100 scale (0 = poor attention and 100 = excellent attention). 1. Identify the independent variable. Dimension: Type of Treatment Level 1: No Ritalin Level 2: Ritalin 2. Identify the dependent variable and its scale. Attention Deficit Scale scores from 0 to 100 (0 = poor attention and 100 = excellent attention) 3. Identify one control variable. had never received treatment for their disorder. Also: Age, diagnosis: all participants were 10 year old males diagnosed with ADHD 4. Identify one random variable IQ 5. Identify the appropriate statistical test: Independent samples t-test (aka t-test for independent means) 6. How many degrees of freedom do you have? (SPSS) df = 18 7. What is your t-obtained value? (SPSS): t-obtained = -1.383 (Remember to interpret as 1.383 in t-table) 8. What is your t-critical values? (look this up in a t-table.): t-critical = 2.101 9. Based on the decision rules listed above, should you Reject or Retain null hypothesis (Ho)? Retain/ fail to reject null hypothesis (Ho) t-obtained (1.383) is not more extreme than t-critical (2.101) 10. Write a paragraph describing the outcome of this study. Figure 1 illustrates the mean Attention Deficit Scale scores for the participants in Group 1 (No Ritalin) and Group 2 (Ritalin). The results indicated similar scores for participants in No Ritalin group (M = 67.4, SD = 10.1) and Ritalin group (M = 73.1, SD = 8.3). An independent-samples ttest did not reveal a significant difference between these two means, t (18) = -1.383, p = .184. The results suggested that participants treated with Ritalin did not display significantly improved academic attention scores in comparison to controls. These results call into question whether Ritalin should be administered to children in academic settings similar to those described in this experiment.