A psychologist obtains a random sample of 20 mothers in the first trimester of their pregnancy. The mothers are asked to play Mozart in the house at least 30 minutes eachday until they give birth. After 5 years, the child is administered an IQ test. We know that IQs are normally distributed with a mean of 100. If the IQs of the 20 children in the study result in a sample mean of 104.2, and a sample standard deviation of 14.7, is there evidence that the children have higher IQs? Use the a = 0.05 level of significance.