Question

The Hurricane Database (HURDAT) has records since 1851 on the most destructive hurricanes. According the HURDAT, hurricane Mitch in 1998 had the highest sustained wind speed of 180mph. Suppose a typo is made when analyzing the top 20 hurricanes of all time in terms of sustained wind speed and this data point is put into the data set as 1800 rather than 180. What effect would this have on the median and IQR in the analysis?

Answer 1

If the speed of 180 is replaced by 1800, the median (which is the mid-point in the ascending or descending order), will move one year towards the higher side, assuming all the speeds are unique.

Effectively, the new median will be higher in value than the correct median had there been no typo.

IQR (Inter Quartile Range) is equal to the difference between 75th and 25th percentiles.

Due to the typo, the 25th (Q1) and 75th (Q3) will undergo change (increase), but their difference may or may not change. So to have the exact effect of the typo on IQR, we should know the actual values of all the data points.