17. The stimulant Ritalin has been shown to increase attention span and improve academic performance in?children with ADHD (Evans, et al., 2001). To demonstrate the effectiveness of the drug, a researcher selects a sample of n = 25 children diagnosed with the disorder, and measures each child’s attention span before and after taking Ritalin. The data show an average increase in attention span of MD = 6.8 minutes with a standard deviation of s = 5.5. Use the sample to make a point estimate and a 90% confidence interval estimate of the population mean difference in attention span produced by the drug.