Question

f) Please answer, in general, what is the effect of the outliers on the descriptive statistics such as mean, standard deviations, median and interquartile range?

Answer 1

f. As mean is sum of all variables divided by total observations, any outlier will have major effect on the mean as it will shift the central value and give the incorrect value.

As standard deviation is correlated to mean, hence if mean is affected by outlier, standard deviation is also affected

Now median are obtained by arranging data in ascending order and considering n/2th value hence here outliers do not have any affect

The IQR is essentially the range of the middle 50% of the data. Because it uses the middle 50%, the IQR is not affected by outliers or extreme values.