What measurement is equal to 6 kilograms

For how answer my question this will be the last question can you answer in math subject

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

[15 points, algebra 2]simplify the complex fraction and find the restrictions.