List<double> list = new List<double>
{1.1,2.2,3.3,4.4};

var result = list.Avarge(x=>x*100)

List<string> str = new List<string> 
{"yahoo","google","pchome","eBay","amazon"};
var result = list.Average(str => str.Length)

var mCOUNT  = db.Products.Count();
var mAVERAGE= db.Products.Average(p=>p.Price);
var mMAX    = db.Products.Max(p=>Price);
var mMIN    = db.Product.Min(p=>Price);
var mMUM    = db.Product.Sum(p=>Price);