Which of the following is a true statement? 1. 37/5 = 5 2/5
2. 32 2/4 = 1/8
3. 9 + 3/7 = 10 3/7
4. 68/5 – 22/5 = 9 1/5

The brain volumes (cm cubed) of 50 brains vary from a low of 904 cm cubed to a high of 1488 cm cubed. use the range rule of thumb to estimate the standard deviation s and compare the result to the exact standard deviation of 175.5 cm cubed, assuming the estimate is accurate if it is within 15 cm cubed