The brain volumes (cm cubed) of 50 brains vary from a low of 902 cm cubed to a high of 1478 cm cubed. Use the range rule of thumb to estimate the standard deviation s and compare the result to the exact standard deviation of 175.2 cm cubed, assuming the estimate is accurate if it is within 15 cm cubed. The brain volumes (cm cubed) of 50 brains vary from a low of 902 cm cubed to a high of 1478 cm cubed. Use the range rule of thumb to estimate the standard deviation s and compare the result to the exact standard deviation of 175.2 cm cubed, assuming the estimate is accurate if it is within 15 cm cubed.