Since there are no given sample statistics, Let us use the following: n=35, x=24.1, and o=2.7
2-tail test
Using a T-test:
t(24.1) = (24.1-23/[2.7/sqrt(35)] = -2.4103
P - value = 2*P(-100< t < -1.9720, when df = 34)
= tcdf (-100,-2.4103,34) -> using excel
= 0.0107
C = pi*d; solve for d.
Divide both sides of this eqn by pi: C/pi = d (answer)