To date the following errors in this STATS article have come to our attention. Please email any additional corrections or comments to btrumbo@csuhayward.edu.

• The last full sentence in the first column of page 4 should begin: The 95% confidence interval for t based on the normal approximation is ... . [That is, replace the first instance of p (pi) in this sentence with t (tau).]

• The parenthetical part of the caption for Table 5 on page 9 should read: (data: 5 positive tests among 215 units of blood). [That is, replace 45 with 5.]

• The second confidence interval, for prior (a), in Table 4 should read: (0.92%, 3.48%). [That is, replace 3.45% with 3.48%.]

• Update: Since this STATS article went to press, we have received a new edition of reference [8], mentioned in the second column of page 4: Pagano, M. and Gauvreau, K., Principles of Biostatistics, 2nd ed., 2000 Duxbury, Pacific Grove, CA. [In the new edition the relevant pages are 141-144.]