a function to average the results of applying other functions in javascript

fnAverage.js

function fnAverage() {
  // Accepts any number of functions as its arguments.
  // Returns a function that averages all the argument functions.
  // Argument functions can accept args. In which case, just pass them into the
  // returned function at call time.
  // Resulting function will error if called with fewer args 
  // than required by function requiring the most args.
  /*
  
  // Example: 
  
  function One(x, y) {
    return x + y;
  }
  
  function Two(a, b) {
    return a * b;
  }
  
  var AvgOneTwo = fnAverage(One, Two);
  
  AvgOneTwo(10, 20) == 115;
  
  AvgOneTwo(1, -4) == -3.5;
  
  */
  var fns = arguments;
  var len = fns.length;
  return function() {
    var args = arguments;
    var tot = 0;
    for (var i=0; i<fns.length; i++) {
      tot += fns[i].apply(null, args);
    }
    return tot / fns.length;
  }
}

// QUESTION: 
// How can this concept be generalized to a generic combining of functions,
// where the the generalized function combinator accepts a list of functions and
// a combining function? The combining function tells it how to "summarize" or 
// combine the result of the application of the argument functions?