20. Finding Critical Values Table A-7 lists critical values for limited choices of

a. Use Table A-1 to add a new column in Table A-7 (down to n 5 15) that represents a significance level of 0.03 in one tail or 0.06 in two tails. For any particular n, use p 5 0.5, because the sign test requires the assumption that P(positive sign) 5 P(negative sign) 5 0.5. The probability of x or fewer like signs is the sum of the probabilities for values up to and including x.