* fix: imgur to s3 for englsh guide without conflict
(cherry picked from commit 9c9f15abf4e755feab79ef7090dacdcf497ea7b6)
* fix: revert unrelated changes
Change 1. corrected typo (deleted the unnecessary backslash in the third example calculation)
original version = -17.25\ ---> revised version = -17.25
Change 2. for greater clarity changed the word "great" to "useful" as follows:
The mean can be a great way to describe a set of numbers. ---> The mean can be a useful way to describe a set of numbers.