A study of MLB players who were born between 1875 and 1930 reported that players whose first names began with the letter D died an average of 1.7 years younger than MLB players whose first names began with the letters E through Z, suggesting that

“Ds die young” [21]. A subsequent study calculated the paired difference in the average age at death for each birth year [22]. For example, for MLB players born in 1900, the average age at death was 63.78 years for those with D first initials and 71.04 years for those with E–Z first initials, a difference of X = −7.26 years. This follow-up study looked at all MLB players, not just players born between 1875 and 1930. Overall, there were 51 birth years with at least five MLB players in each category and the 51 values of X had a mean of −0.57 and a standard deviation of 6.36. Calculate the two-sided P value for a test of the null hypothesis that the population mean is 0. How would you explain the fact that the two-sided P value was lower in the original study than in the subsequent study?