Researchers once reported that 1969–1990 California mortality data show that Chinese-

Americans are particularly vulnerable to four diseases that Chinese astrology and traditional Chinese medicine associate with their birth years [19]. The two-sided P values were 0.022, 0.052, 0.090, and 0.010. However, a subsequent study [20]

using data for 1960–1968 and 1991–2002 found the two-sided P values to be 0.573, 0.870, 0.235, and 0.981. How would you explain this discrepancy?