Final answer:
In statistics, a nonresistant measure is not affected by outliers. To determine if an outlier is influential, it can be removed from the data set to see its impact on the best-fit line and correlation coefficient.
Step-by-step explanation:
In statistics, if a measure is nonresistant, it means that its value is not affected by outliers.
An outlier is a data point that is significantly different from the other data points. It may be an error or abnormality in the data.
To determine if an outlier is influential, you can remove it from the data set and see if it significantly impacts the slope of the best-fit line and the correlation coefficient.