Most serious Hold'em players understand that the modern game has become more and more about frequencies. Not many really understand that a range is a frequency and that a frequency can be a range, and as a percentage.
We all know about ranges preflop. If you check your range with Flopzilla, you will see a percentage. At the bottom of the range matrix is both a percentage number and a combos number. There are 1326 combinations of 2 cards. The median is 663 combos. A 10% range would be 1362 combos. With 132 you will bet or call 10% of your hands.
If you use Holdem Manager, you will see VPIP Voluntarily Put In Pot, and PFR Pre-Flop Raise as percentages. In fact, almost everything in their report is in percentages. If it is a percentage, then it can probably be represented as a range. Every percentage has an optimum range. An overall VPIP of 20% is good, a VPIP of 40 is a Fish and a VPIP of 5 is a NIT.
Let's see how a percentage or frequency can be implemented. If you want to bluff on the Flop 50% of the time time, you can use the color of the first card first dealt to you, black bluff, red no bluff. This will get you to the frequency that you want but is not a good way to do it. It means that there is no logic to your bluffs, no consideration of the value of the cards that you hold. A bluff range can include the best cards that you will not open with. Don't bluff with 72o. Bluff with hands that have a better chance of winning but were not good enough to bet for value.