Filtering is a function of what? a switches b servers c nodes d ports

Which statistical function in a spreadsheet you to see how far each number varies, on average, from the average value of the list?

Suppose there is a relation r(a, b, c) with a b+-tree index with search keys (a, b).1. what is the worst-case cost of finding records satisfying 10 < a < 50 using this index, in terms of the number of records n1, retrieved and the height h of the tree? 2. what is the worst-case cost of finding records satisfying 10 < a < 50 and 5 < b < 10 using this index, in terms of the number of records n2 that satisfy this selection, as well as n1 and h defined above? 3. under what conditions on n1 and n2, would the index be an efficient way of finding records satisfying the condition from part (2)?

2. fluorine and chlorine molecules are blamed fora trapping the sun's energyob forming acid rainoc producing smogod destroying ozone molecules