I want to test a claim that the mean waste generated by adults in the country is more than 3.5 pounds per

I want to test a claim that the mean waste generated by adults in the country is more than 3.5 pounds per person/day. In a random sample of 9adults in the country, I find that the mean waste generated per person is 4.3 pounds per day with a standard deviation of 1.2 pounds.  At .01can I support the claim.  

I found the critical value To = 2.897.     I need to find the standardized Test Statistic (t)