It's common for a child's first tooth to come in crooked and require dental surgery once they get older as a result. A dentist used x-rays to measure the angle (in degrees) of distortion in a random sample of 40 patients under the age of 10 who came to a dentist office for surgery to straighten their first tooth. The more severe the angle of the tooth, the more serious. For these 40 patients, the mean angle of deformity was 13.5 degrees and a standard deviation of 3.4 degrees. Construct and interpret a 90% confidence interval for the mean angle of deformity in the population of all such patients.