Net effect of weather derivatives on cash holdings divided by assets: The availability of weather derivatives increases the cash holdings divided by assets by () %

The lee family is looking to buy a house in one of two suburban areas just outside of a major city, and air quality is a top priority for them. overall air quality is calculated by taking measures in 100 locations within each suburb and then calculating a measure of central tendency. in one suburb, there is a major bus station that creates very poor air quality at its location but has no impact in the surrounding parts of the suburb. in this situation, which measure of overall suburb air quality would be most useful?