Input program.
	Loop #i = 1 to 25.
		*The function rv.uniform(1,1) draws a uniformly (flat) distributed
			random number between 0 and 1.
		* Decide on a door.
		Compute door = rv.uniform(0,1).
		*Decide on the winner.
		Compute winner = rv.uniform(0,1).
		Recode door, winner (lowest thru .3333 = 1) (.33334 thru .6666 = 2) 
			(.6667 thru highest = 3).
		*Decide on Switching.
		String switch (A3).
		compute x = rv.uniform(0,1).
		If (x le .5) Switch = 'No'.
		If (x gt .5) Switch = 'Yes'.
		*Now carry out the switch if necessary--though not very elegantly.
			* If you guess the right door and switch, it is not important which door you
				switch to.
		If (Switch = 'Yes' and door = 1 and winner = 1) door = 2.
		If (Switch = 'Yes' and door = 1 and winner = 2) door = 2.
		If (Switch = 'Yes' and door = 1 and winner = 3) door = 3.
		If (Switch = 'Yes' and door = 2 and winner = 1) door = 1.
		If (Switch = 'Yes' and door = 2 and winner = 2) door = 3.
		If (Switch = 'Yes' and door = 2 and winner = 3) door = 3.
		If (Switch = 'Yes' and door = 3 and winner = 1) door = 1.
		If (Switch = 'Yes' and door = 3 and winner = 2) door = 2.
		If (Switch = 'Yes' and door = 3 and winner = 3) door = 2.
		String win (A3).
		If door eq winner win = 'Yes'.
		If door ne winner win = 'No'.
		End Case.
	 End Loop.
	End File.
End Input Program.



*Now let's table all the results and see what we get.
Crosstabs /Tables = switch by win
		/Cells = count row
		/Statistics = chisq.