# Die Studies Statistics

 Number of obversesNumber of obverse dies. ᵖ (o) Number of singletons (o1)The number of singleton coins. ᵖ Number of reverse diesNumber of reverse dies. (r) Number of coinsNumber of coins. (n) Coins per obverse dieNumber of coins per obverse die. (n/o) Coins per reverse dieNumber of coins per reverse die. (n/r) Reverse per obverse ratioRatio of obverse dies divided by reverse dies. (r/o) Percentage of singletons (o1)number of coins (n) divided by the number of singletons (o1) ᵖ Original number of dies (O) (Carter 1983 formula)The estimation of the number of coins according to Carter 1983 ᵖ Coins struck if 20,000 as average productivity per dieCoins made if the average productivity for obverses (according to Carter) is 20,000. ᵖ Original number of dies (O) (Esty 2011 formula)The estimation of the number of coins according to the singleton formula in Esty 2011 ᵖ (O) Survival rate if 20,000 as average productivity per dieSurvival rate if average productivity is 20,000. ᵖ Coverage (o = % of O) (Esty 1984 formula)Esty 1984 - coverage (% of O) ᵖ (o = % of O) Die productivity if survival rate 1/2,000Average productivity if survival rate is 1/2,000. ᵖ Weight of silver (in kg) if 20,000 coins per die (O = Carter formula)Carter 1983 * Median weight * 20000 (*10 if gold or electrum) ᵖ Die productivity if survival rate 1/5,000Average productivity if survival rate is 1/5,000. ᵖ