Question

How many standard deviations away from the mean do you think a data value needs to be in ordered to be considered an outlier (unusual) and discuss your reasoning for your choice.

Answer 1

3 standard deviations away

Explanation:

Three (3) standard deviations away from the mean of the data is common practice of consideration of an outlier. 3 is considered the default value and threshold for most data distributions similar to Gaussian like distributions.

Standard deviations are very sensitive to outliers and a unit alteration or change can cause substantial effect on the standard deviation. Some data distribution have similar mean, but standard deviations can alter with the spread.