I'm not sure you understood me. I want to specifically avoid doing all that, to save time and effort.

Alas, I don't know a faster way. The question asked, iiuc, demonstrates a lack of understanding of standard deviation. That's fine; none of us know everything. But without that we can't intepret the results, and also necessary is understanding what the scale represents. Thus the fastest solution seems to be reading the author's interpretation rather than trying to do it yourself.