Los números racionales nos sirven para cuidar el agua​

Aman steps out of a plane at a height of 4,000m above the ground falls 2,000m very quickly and then opens his parachute and slowly falls the remaining 2000m to the ground what height above the ground would be the best choice for a reference point

Sum is 17 and their difference is 3

Compute the standard deviation of the following set of data to the nearest whole number. 10, 10, 15, 20, 25