hexagon logo

GR&R- help!!

I am testing my GR&R so I am manually putting in data, I made my tracefields (operator,part,trial), my data values are in along with transactions, when I click on the GR&R icon I select all the transactions and the variable. now the problem is when I get to the GR&R selection box i get a message that says TRANSACTION ENTERED WAS INVALID! what does this mean?? i also have another question i a assuming that trial means how many times you measured the part?