What critical value of t* should be used for a 99.5% confidence interval for the population mean based upon a random sample of 18 observations? Find the t-table here.

t* = 2.878
t* = 2.898
t* = 3.197
t* = 3.222

You just purchased two coins at a price of $670 each. because one of the coins is more collectible, you believe that its value will increase at a rate of 7.1 percent per year, while you believe the second coin will only increase at 6.5 percent per year. if you are correct, how much more will the first coin be worth in 15 years?