- mixing and sorting .
- ranking;
- each element receives a rank corresponding to its position in the list.Element whihc have the same value receive the same rank:
- compute rank sums Ra,Rb
like this.- for these sums,the following always holds:
- compute sample statistics Ua,Ub
- like this.
- where the following always holds: Ua+Ub=nanb------>7+41=6*8=48
- like this.
- set U=min {Ua,Ub}
- U=min {Ua,Ub}=min{7,41}=7
- compute critical Uα values
- for the significant level α the critical Uα value s can be computed for the two-sided test as:
- where z is the "probity "function ,the inverse cumulative distribution function of the standard normal distribution .
- the value of z can be looked up in the standard normal distribution table appendix .
- for the significant level α the critical Uα value s can be computed for the two-sided test as:
- U < Uα => different between Ua and Ub significant
- the different between Ua and Ub is significant at an error level a only if U is smaller than Ua.
- if U < Ua,and Ua < Ub:A is from a distribution with a smaller median than B (this is wrong with a probability of no more than a )
- for this example :
like this.
时间： 2024-10-10 10:18:51