Australian and US coins have some similarities but many differences. Images and data are readily available on the “net” and make for rich areas of investigation. The following data was obtained from the Royal Australian Mint website, and Coins of the United States dollar on wikipedia.
The Australian coins currently in circulation, (as pictured above) are 5, 10, 20 & 50 cents (loosely referred to as silver coins); and 1 & 2 dollar (loosely referred to as gold coins). All are circular with the exception of the 50 cents which is a dodecagon. The “copper” 1 & 2 cent coins were withdrawn from circulation in Feb 1992.
1. Aussie Coins coefficient of determination (R squared) = 0.067, this increases to 0.80 if the 1 & 2 dollar coins are omitted.
2. US Coins coefficient of determination = 0.505 which increases to 0.984 if the 10 cent and 1 dollar are omitted.
1. Which country has a high correlation between the variables above?
2. Are other variables more highly correlated eg. value of metal content
3. What other shaped coins are used in other countries? See World Coins website.
4. What change is possible for 1USD? 1AUD? 1 British Pound? (stayed tuned for next post!)