From
http://www.forexfactory.com/showthread.php?p=1481562:
"As far as I can tell, High/Low uses the following formula to calc %K:
100 x (Recent Close - Lowest Low*) / (Highest High* - Lowest Low*)
[* for the last N periods, where N is the %K parameter]
whereas Close/Close uses the following formula to calc %K:
100 x (Recent Close - Lowest Close*) / (Highest Close* - Lowest Close*)"
So, changing the Price Field setting changes the price used in calculating the %K line. The stochastic indi has 2 lines: %K (fast) and %D (slow). The %D line is a slowed version of the %K line. So if you change the price used in the calculation of the %K line, you are thereby changing the calculation of the %D line as well--you are changing the entire indi.
For the entire stochastic calculation, visit the link at the top of this post. If you want more reading, visit the link at the top of
that post. To watch the indi in action, go to your standard Indicators folder in MT4 (not Custom Indicators), attach the Stochastic Oscillator, and change the Price Field setting. For a working EA example, simply build the mol in SB and select 0's or 1's.