What are outliers in a data set?

Outliers are defined as data points that significantly differ from the rest of the values in a data set. They can stand out due to being much higher or lower than the other observations and may indicate variability in the measurement, experimental errors, or a different phenomenon that is worthy of further investigation.

Identifying outliers is crucial in statistical analysis because they can skew results and lead to misleading conclusions if not addressed appropriately. Their presence can affect calculations of mean, standard deviation, and even data visualization, which underscores their importance in understanding the overall pattern of the data.

The other options do not accurately reflect the concept of outliers. Identical data points would indicate consistency, statistical irrelevance does not pertain to the distinction of being an outlier, and average values represent central tendencies rather than points that are significantly different.