Explain statistical method are dangerous weapons …

The above statement pertains the limitation of statistics as given below: 

It indicates that statistics can be used only by those persons who have special knowledge of statistical methods. The techniques of statistics are not so simple to be used any layman. Those who are ignorant about these methods cannot make sensible use of statistics, leading to dangerous consequences. The statistical techniques can be used only by the experts as they are complicated in nature. A layman can misuse statistics and draw any type of conclusion he likes.  For example, a person who is not well versed with statistical methods may assume that the average age of 20 persons represents the actual age of those 20 persons. However, this is not true. Out of those 20 persons, some of them will be aged below 20 years, some above 20 years and a few can be aged 20 years.