Constructing a Network Diagram, given an Activity Table.

[Yendall]

Hey,
If I get given an activity table like this one:


How would I place each node and how would I incorporate the weights of each edge?
If:
A, B and C do not have predecessors, so am I to assume there are three edges coming off the first node? like so:

Also, when one node has two predecessors, does that mean that two edges go to the one node? 
Like say Activity E is preceded by activity B and D, it would look something like this:


Am i doing this right?

Thanks for any help.

[plato]

Your start is good but you must make it a digraph by inserting arrows. A sketch of a flow diagram may be in all directions until it is tidied up and, without arrows, it may be confusing about the sequance of activities. You should not assume that it must always be read from left to right only.

Also look ahead when drawing in an activity. Activity F has A and E as predecessors so you could terminate A and E at the same node from which F would commence. But, this COULD cause a problem if there was another activity that had only A OR E as a predecessor. Imagine another activity L had A ONLY as a predecessor. In that case, you would terminate both A and E at different nodes and make a dummy connection from A to E. You then commence activity L from the end of A and Activity G would commence from the end of activity E where the dummy from A meets to indicate that A is also a predecessor for G.

You started activities A B and C from a starting node but your table as shown does not indicate a single end node. In my sketch, activities F G and K do not have a follow-on activity and so these should all be drawn terminating at the one final node.

[Yendall]

Thank you for replying!
So i've reconstructed the diagram and ended up with this:

I noted the end node (my diagram was incomplete when i posted this). Is this diagram the correct construction?
I also added the flow arrows, however I'm a little skeptical about activity E (it looks like it is flowing backwards). Should I correct an error like this, or is the flow assumed to always flow forward?

[plato]

Your diagram is fine. Activity E only looks as though it is going "backwards" beacuse the end node of activity A is drawn to the left of the end node of activity B. The arrows really are far more important than where the nodes are actiually drawn as the arrows will always indicate the direction of the "flow" from an activity to the next.

[Yendall]

Your diagram is fine. Activity E only looks as though it is going "backwards" beacuse the end node of activity A is drawn to the left of the end node of activity B. The arrows really are far more important than where the nodes are actiually drawn as the arrows will always indicate the direction of the "flow" from an activity to the next.

Okay I see what you mean. Do you think I would lose marks if my diagram was slanted like the one above?
As long as the directional arrows indicate the overall flow of the activity it shouldn't matter?