[R] visualizing frequencies

[Mag. Ferri Leberl]

Dear everybody,

In our game-theory lesson we have run several classroom-experiments where the 
students had to decide for a natural number between one and seven. I have 
troubles now to visualize the results: be a the vector of answers.

hist(a) will not assume natural numbers as answers, but rational. It will make 
the brakes exactly at the natural numbers,  which is difficult to interpret, 
as only natural numbers may be employed.

barplot(a) or barplot(a,1:7) will not aggregate the answers. If three students 
returned the number seven, it will show three bars to the size of seven 
instead one bar to the size of three on index seven.

barplot(1:7,a), in this case, will show the bar at index seven, wut it will be 
to the hight of seven and to the width of three.

I also wanted to show the results of the different versions of the experiment 
in ONE plot. As the number of participants varied I googled around in the 
R-Archives and got to recognize plot.edf. As a pitty, this function seems to 
set the index the wrong way round: the function starts with the number of 
students deciding for seven, but indexes them with one.

Can anybody help me with these two problems?
Thank you in advance!