I have an excel file containing a table where I registered the frequency of three linguistic phenomena in 72 poems. Since the poems have different lengths I normalized the results dividing each value by the number of tokens of each poem and multiplying per 100. After that, I opened orange, added a new file, connected data table and selected the table. At this point, I connected PCA and with two components I have 97% explained variance but only if I deselect the "normalize variables" option and then I have a nice scatter plot.
My question is the following: when do I need to use the "normalize variables" option? Because in this case, I deselected it because I had already normalized the data. However, I am not sure if I made any mistakes.