Are you smarter than your older brother? In a study of birth order and intelligence, IQ tests were given to 18- and 19-year-old men to estimate the size of the difference, if any, between the mean IQs of firstborn sons and secondborn sons. The following data for 10 firstborn sons and 10 secondborn sons are consistent with the means and standard deviations reported in the article. It is reasonable to assume that the samples come from populations that are approximately normal. Can you conclude that the mean IQ of firstborn sons is less than the mean IQ of secondborn sons? Let W denote the mean IQ of firstborn sons and I, denote the mean IQ of secondborn sons. Use the @ = 0.01 level and the P-value method with the table. Firstborn 103 83 101 97 128 90 113 108 88 104 Secondborn 102 104 90 114 101 104 91 91 113 114