To delve (into) a subject or situation is to investigate, explore, or research. It has the connotation of being more thorough than merely "looking into."
put upon "Three wise men came bearing gifts." = carrying"Her bearing was as a ballet dancer." = deportment"He took his bearing from his pocket compass." = direction"The wheels contained twelve ball...
'Mean' in this context means 'average'. Thus, 'mean word length' means 'average word length'. This is the total number of letters in your piece of writing, divided by the total number of words.Here...