Explore the time line of statistics since 450 BC when Hippias of Elis uses the average value of the length of a king’s reign (the mean) to work out the date of the first Olympic Games, some 300 years before his time. then you will see 840 Islamic mathematician Al-Kindi uses frequency analysis – the most common symbols in a coded message will stand for the most common letters – to break secret codes. Al-Kindi also introduces Arabic numerals to Europe.

http://www.statslife.org.uk/images/pdf/timeline-of-statistics.pdf

The earliest writing on statistics was found in a 9th century book entitled: "Manuscript on Deciphering Cryptographic Messages", written by Al-Kindi (801–873 AC). In his book, Al-Kindi gave a detailed description of how to use statistics and frequency analysis to decipher encrypted messages, this was the birth of both statistics and cryptanalysis.