Hi
Ho: p >= 12.500 (claim)
Ha: p <12,500
-----------------------------------------
Sample:
mean = 12031
s = 1606.595
---
test stat:: z(12031) = (12031-12500)/[1606.6/sqrt(10)] = - 499/508.1 = -.9821
-----
p-value = P(z < -.9821) = .1630
Conclusiion:
Since the p-value is greater than .01, accept claim.
The test results support the claim.