A research team is interested in the difference between serum uric acid levels in patients with and without Downs Syndrome. In a large hospital for the treatment of the mentally retarded, a sample of 12 individuals with Down Syndrome yielded a mean of 4.5mg/100ml. In a general Hospital, a sample mean of 15 normal individuals of the same age and sex were found to have a mean value of 3.4mg/100ml. If it is reasonable to assume that the two populations of values are normally distributed with variances equal to 1 and 1.5, find and interpret the 95% confidence interval.