For a MannWhitney test, the hypotheses are as follows.
 Null hypothesis

H_{0}: η_{1} = η_{2} 
The median of the first population (η_{1}) equals the median of the second population (η_{2}). 
 Alternative hypothesis
 Select one of the following alternative hypotheses.
H_{1}: η_{1} ≠ η_{2} 
The median of the first population (η_{1}) does not equal the median of the second population (η_{2}). 
H_{1}: η_{1} > η_{2} 
The median of the first population (η_{1}) is greater than the median of the second population (η_{2}). 
H_{1}: η_{1} < η_{2} 
The median of the first population (η_{1}) is less than the median of the second population (η_{2}). 