Question

Part 2: Wilcoxon Rank-Sum Test

Let us consider another hypothetical situation. The WHO wants to compare the mortality rates of children under the age of five years of underdeveloped and developed regions of the world. There were two independent samples of ten countries from each of the groups drawn at the same time, and the yearly mortality rates of children under the age of five years (per 100,000) inhabitants were reported (MRate1 and MRate2).

Table 2: Mortality Rates of Children

Country	MRate1	MRate2
1	120	11
2	110	9
3	105	13
4	61	11
5	45	14
6	114	11
7	118	10
8	138	8
9	85	6
10	70	6

Using the Minitab statistical analysis program to enter the data and perform the analysis, complete the following:

• Run the Wilcoxon rank-sum test to show whether there is a statistically significant difference between the mortality rates of children under the age of five years of the regions. Results may be used in making decisions regarding which region needs to receive help to improve the public health issues of morality.
• Obtain the difference in the mortality rates and whether there is a statistically significant difference.
• In a Microsoft Word document, provide a written interpretation of your results.

Answer 1

Mann-Whitney Test and CI: MRate1, MRate2

         N Median
MRate1 10 107.50
MRate2 10   10.50

Point estimate for ETA1-ETA2 is 98.00
95.5 Percent CI for ETA1-ETA2 is (59.00,108.00)
W = 155.0
Test of ETA1 = ETA2 vs ETA1 not = ETA2 is significant at 0.0002
The test is significant at 0.0002 (adjusted for ties)

Since P-value<0.05 so there is significant difference in the mortality rates.