Question

In your own words, explain what an outlier is.

Answer 1

Solution :-

Outlier :-

An outlier is an observation that lies outside the overall pattern of a distribution A convenient definition of an outlier is a point which falls more than 1.5 times the Interquartile range above the third quartile or below the first quartile.

One way to define an outlier is  anything below Q1 – 1.5 IQR or above Q3 + 1.5 IQR. This is called the 1.5 x IQR rule.

For example in the scores 3,25,27,28,29,32,33,85 both 3 and 85 are "outliers".

Extreme outliers are any data values which lie more than 3.0 times the interquartile range below the first quartile or above the third quartile.

Outliers affect the mean value of the data but have little effect on the median or mode of a given set of data.

An outlier may be due to variability in the measurement or it may indicate experimental error; the latter are sometimes excluded from the data set. ... Outliers can occur by chance in any distribution, but they often indicate either measurement error or that the population has a heavy-tailed distribution.