Q. 197  A statistically unusual observation or an outlier is of special interest many a times. However, an outlier is ignored or removed from data set sometimes. What are the factors that help one decide if an outlier is to be considered and investigated or if it can be ignored safely?    Note for website visitors - Two questions are asked every week on this platform. One on Tuesday and the other on Friday. All questions so far can be seen here - https://www.benchmarksixsigma