=+17. Quality control. A farmer is claiming that the apples he produces are categorized, according to their size, as small, medium and large and that the percentages of each category are: 25% small, 45% medium and 30% large apples.

You collect the production of some trees and separate the various categories. You find that there are 55 kilograms of small apples, 120 kilograms of medium apples and 85 kilograms of large apples. You wonder whether your mix is significantly different from what the farmer is claiming.