Nine independent measurements are made of the length of a rod. The average of the nine measurements is X̅ = 5.238 cm, and the standard deviation is s = 0.081 cm.

a. Is the uncertainty in the value 5.238 cm closest to 0.009, 0.027, or 0.081 cm? Explain.

b. Another rod is measured once by the same process. The measurement is 5.423 cm. Is the uncertainty in this value closest to 0.009, 0.027, or 0.081 cm? Explain.