What is the effect of concussions on the brain? Researchers measured the brain sizes (hippocampal volume in microliters) of 25 collegiate football players with a history of clinician-diagnosed concussions and 25 collegiate football players without a history of concussions. The table shows the summary statistics. Standard Deviation Group Group Size Concussion 25 609.3 Nonconcussion 25 815.4 Is there evidence of a difference in mean brain size between football players with a history of concussions than those without concussions? Let \"C be the mean brain size for players who have had concussions, and let \"NC be the mean for those who have not had concussions. Select the appropriate hypotheses that best describe this research question. Find the standard error, SE, and t-statistic, t, and the P-value for these data and make appropriate Conclusions about the brain size of football players. (Enter your answers rounded to four decimal places.)