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 firstborn sons and 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 greater than the mean IQ of secondborn sons? Let , denote the mean IQ of firstborn sons. Use the a= 0.05 level and the critical value method with the table. Firstborn 115 128 108 114 126 105 129 109 109 117 Secondborn 96 86 106 96 84 110 129 98 118 129