An outlier in a given data is one of the values that is far greater or lesser compared to others. It affect the mean and standard deviation of a given data significantly.
From the given data, 18 is far too small compared to other values. This is certainly an outlier. This would affect the mean speed by decreasing the value.
An interquartile range is a measure of differences among data by dividing a set of given data into quartile. Increasing the value of the outlier would increase the interquartile range.
