PS296 Chapter 2: Notation
Notation:
-no standard notational system has been adopted
-the most complex systems gain precision at the loss of easy intelligibility
-however the simpler systems gain intelligibility at the loss of some precision
-loss of precision is usually minor when compared with the gain in comprehension
-a variable will be represented by an uppercase letter
-often X or Y
-an individual value of that variable will be represented by the letter and a subscript
ex : 45 42 35 23 52
-set of scores referred to as X
-the first number (45) is X1
-second (42) is X2 and so on
-to refer to a single score w/o specifying which one, we refer to Xi, where i can take on any
value between 1-5
Summation Notation:
-add up, or sum, what follows
-most common symbol is uppercase Greek sigma Σ
-thus Σxi is read: sum the Xis
Document Summary
The most complex systems gain precision at the loss of easy intelligibility. However the simpler systems gain intelligibility at the loss of some precision. Loss of precision is usually minor when compared with the gain in comprehension. A variable will be represented by an uppercase letter. An individual value of that variable will be represented by the letter and a subscript ex : 45 42 35 23 52. To refer to a single score w/o specifying which one, we refer to xi, where i can take on any value between 1-5. Most common symbol is uppercase greek sigma . X2 = sum the squared values of x (ex 452 + 422 + 352 + 232 + 522) Xy = sum the products of the corresponding values of x and y. Rules of summation: (x y) = x y, cx = c x. Cx means to multiple every value of x by the constant c and then sum the results.
