4. The average IQ of 48-month old girls is 108. A random sample of 30 adopted girls was found to have a mean IQ of 103 with a standard deviation of 18. Is it reasonable to conclude that the mean IQ of adopted girls is different from that of the general population of 48-month old girls? Please answer the question by providing (a) two hypotheses along with assumptions, (b) significance level (use 0.05 level), (c) critical values with appropriate df, (d) decision rules, (e) computations, and (f) decision and interpretation.