Normal Curve Outliers


Less is more. Stay pure. Stay poor.
You get to pick. Plus or minus 2 std would include 95% of data and 3 std ~99%. Values will land out there but you should visualize them with histogram or boxplot to see if they really are an outlier.
Thanks hlsmith. So you are saying that there is no consensus. I understand. Seems to me most choose z>2 (or z<-2)
Possibly because of the choice of popular 95% for confidence intervals. I'm curious whether the 1.5*IQR decision for
outliers would confirm 2 or 3. Thanks for your response.


Well-Known Member
I prefer the Tukey's fences you mentioned.
you can calculate the confidence interval using 1.5*IQR under the assumption of normality (Q1=Z0.25, Q3=Z0.75) ...