super newbie here.

just a quick question:

I have been doing one tailed independent two sample t tests but now on other data I no longer have normal distributions so I wanted to use Mann Whitney U test, but I am not sure if these can be one tailed.

I am using R so is it legitimate to specify the "alternative" argument as greater and if so (Im assuming so since it is an available option in R) do I then divide p/2 as I would for the t test to get a one tailed p value?

any advice is appreciated.

cheers

J