GATE 2022 ST – Question 51
Independent size-seven samples are population 1:(18,20,16,20,17,18,14) and population 2:(17,18,14,20,14,13,16). For the two-sided 5% Mann–Whitney test of equal distributions,find the U statistic as an integer.
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Correct answer: 15 to 15
Explanation
Use average ranks for pooled ties. For values 13,14,16,17,18,20,the midranks are 1,3,5.5,7.5,10,13. Population 1 rank sum=10+13+5.5+13+7.5+10+3=62. Its U is 62−7·8/2=34;the other U is 49−34=15. The two-sided statistic is min(34,15)=**15**.