There is no agreed definition of an outlier and consequently, there is no simple answer to the question. The number of outliers will depend on the criterion used to identify them.
If you have observations from a normal distribution, you should expect around 1 in 22 observations to be more than 2 standard deviations from the mean, and about 1 in 370 more than 3 sd away. You will have more outliers if the distribution is non-normal - particularly if it is skewed.
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They are called outliers
Data that does not fit with the rest of a data set is known as an outlier. Outliers can skew statistical analyses and distort the interpretation of data. They can be caused by errors in data collection, measurement variability, or may represent true but rare occurrences in the data set. Identifying and handling outliers appropriately is crucial in ensuring the accuracy and reliability of data analysis results.
an outliers can affect the symmetry of the data because u can still move around it
Each outlier is a single point in the outcome space.
Outliers