TER 12 approximated by the normal distribution. For a large number of ties, Equation 14.26 may not be correct For the data in Table 14.18, TR-9.5 with won + 1) 1042) 115 and Varl) - Malawi + 1) 2M 12 Notice that the variance of the sampling distribution of the Wikoxon rank um statistic. T. in the same as the variance of the sampling distribution of the Mann-Whitney statistie, El. It follows that TAI VI 11 -1.42 ---value = 0.1956 V 230 Example 14.14 Earnings for Two Firms (Wilcoxon Ranic Sum Test) In a study designed to compare the performance of firms that give management forecasts of earnings with the performances of those that do not independent ran dom samples of 80 firms from each of the populations were taken. The variability of the growth rate of earnings over the previous 10 periods was measured for each u33 1 Nope Test for Independent landum Sempus 611 of the 160 firms, and these variabilities were ranked. The sum of the ranks for firms not disclosing management earning forecasts was 7,257 (Jaggi and Grier 1980). Test, against a two-sided alternative, the null hypothesis that the central locations of the population distributions of eaminge variabilities are the same for these two types of firms. Show that the results are the same with both the Mann-Whitney U test and the Wilcoxon rank sum test