Decision - Critical Path Analysis

Question 1

What is a precedence table?

Answer 1

A precedence table is a table in which shows when activities must be competed before others are started

But only the immediate dependence is shown

Question 2

What is another name for a precedence table?

Answer 2

Dependence table

Question 3

Have a general idea what a precedence table looks like

Answer 3

Question 4

What is a dependency?

Answer 4

When one activity can’t proceed until another activity is completed it is referred to as a dependency

Question 5

How can you represent a precedence table as a network?

Answer 5

An activity network

Question 6

In an activity network what do the arcs represent?

Answer 6

Activities

Question 7

In an activity network what do the nodes represent?

Answer 7

The completion of the activities

Question 8

What are activities also called?

Answer 8

Events

Question 9

What must be on each arc in an activity network?

Answer 9

An arrow to show which way the production process happens
And an activity letter

Question 10

What is the first node labeled?
What is it called?

Answer 10

0
Source node

Question 11

What is the final node called?

Answer 11

The sink node

Question 12

When creating an activity network where do the numbers come from?

Answer 12

You add the numbers once you draw a line from that activity (do them in order from A-Z)

Question 13

What may be different about the source node sometimes?

Answer 13

It may have a start label of 1 instead of 0

Question 14

What is the exam tip with activity networks?

Answer 14

You are most likely going to need to do a couple tries so don’t try to do it first time

Question 15

What is a dummy variable?

Answer 15

A dummy node can show that an event C depends on events A and B, which are not dependent on each other and therefore are impossible to connect on a graph

Question 16

State the standard example of a dummy variable?

Answer 16

Question 17

What does a dummy variable have none of?

Answer 17

It has no time or cost

Question 18

What is a dummy variables sole purpose?

Answer 18

A dummy variables sole purpose is to show dependencies between activities

Question 19

What does a dummy variable look like?

Answer 19

A dummy variable is represented by a dotted line (with an arrow in the correct way in which you will continue the graph

Question 20

What is the early event time?

Answer 20

The early event time is the earliest time of arrival at the event allowing for the completion of all preceding activities

Question 21

What is the late event time?

Answer 21

The late event time is the latest time that the event can be left without extending the time needed for the project

Question 22

How do you calculate the early event time?

Answer 22

The early event times are calculated starting from 0 at the source node and working towards the sink node by adding the value of each arc to the previous early event time
This is called a forwards pass or forwards scan (you always use the largest number)

Question 23

How do you calculate the late event time?

Answer 23

The late event times are calculated starting at the sink node and working backwards towards the source node. This called a backwards pass or backwards scan
It is calculated by subtracting the previous late time by the number on the arc (you always choose the smallest number

Question 24

When doing questions with early and late times what changes with the graph?

Answer 24

You replace the nodes with:

Question 25

What is a critical activity?

Answer 25

Critical activity - an activity in which any increase in its duration results in a corresponding increase in the duration of the whole project

Question 26

What is a critical path?

Answer 26

Critical path - a path from the source node to the sink node which entirely follows critical activities

Question 27

What will be true about a critical path?

Answer 27

It will be the longest path

Question 28

What is the easy way to see where a critical activity is?

Answer 28

Any node which has an early time = late time is a critical activity

Question 29

What do you need to mention when explaining why a activity is critical?

Answer 29

An increase in the time to do with activity will lead to an increase in the whole project time

Question 30

What is the total float of a critical activity?

Answer 30

0

Question 31

What is the total float of an activity?

Answer 31

The total float of an activity is the amount of time that its start may be delayed without affecting the duration of a project

Question 32

How do you calculate total float?

Answer 32

Total float = latest finish time - duration - earliest start time Bottom Right - Middle - Top Left

Question 33

How do gantt charts represent a critical path?

Answer 33

It is put continuously across the top of the graph

Question 34

What does a gantt chart do?

Answer 34

A gantt chart provides a graphical way to represent the range of possible start and finish times for all activities on a single diagram

Question 35

How do you draw a gantt chart?

Answer 35

Draw the boxes of the critical path at the top Then on the second line draw in a box representing the first non critical activity (you need to draw the start of the box at the earliest start time and then draw dotted box to represent its float which ends at the latest time) Continue this process

Question 36

What is a gantt chart also called?

Answer 36

Cascade graph

Question 37

What is a big mistake when drawing gantt charts?

Answer 37

Forgetting to draw in the float of the activities

Question 38

If you asked to state which activities must be happening at 10 days, what do you do?

Answer 38

you draw a line down your Gantt chart and any activities that are through the line (and can't be shifted to the left or right because of their float) are the answer

Question 39

What are the assumptions of the resource diagrams?

Answer 39

No worker can do more than 1 job at a time Once a worker has started an activity , they must complete it The worker becomes avaliabke for another activity immediately after finishing the previous activity

Question 40

What can resource histograms be used for?

Answer 40

Considering how many workers are required to complete a project in minimum time

Question 41

When drawing an initial resource histogram what else do you assume.

Answer 41

Each activity starts at the earliest time possible

Question 42

What is it called when you move around the start times of activities?

Answer 42

Resource leveling

Question 43

What is resource levelling (definition)

Answer 43

The process of adjusting the start/finish times so that the project can use less workers

Question 44

What is the first step when drawing a resource histogram?

Answer 44

You draw in your critical path along the bottom

Question 45

How do you draw a histogram (from a ghant chart)?

Answer 45

Draw critical path along the bottom From top to bottom on the gantt chart (starting as soon as possible) each event It may be quicker to draw it day by day

Question 46

When resource levelling what do you nit want to do (with what exception)?

Answer 46

You don't want to move an activity outside its float. If it is necessary, do this with the critical activities

Question 47

How do you draw a resource histogram from an activity network?

Answer 47

Draw a precedence table then keep an eye on the dependencies and the start and finish times from the activity network

Question 48

What is a scheduling diagram?

Answer 48

A scheduling diagram is a diagram which shows how all the activities can be completed with the minimum number ow workers (Probably not a good definition)

Question 49

How do you draw a scheduling diagram?

Answer 49

Always assume worker 1 does the critical activities Worker 2 will start with the next activity with the earliest finish time You start with the top row then work your way down You shade in any wasted time

Question 50

Explain what is meant by a critical path?

Answer 50

A chain of activities which have no float

Question 51

How can you tell from an activity network which activities should be happening on day 20?

Answer 51

Look at the start and end times. If the start time is lower than 20 and the finish time later than 20 then look at the length. Use your brain to see if that has to occur during the 20th day

Question 52

How do you calculate a lower bound for the number of workers required?

Answer 52

Then round up as you can't have .3 of a worker

Question 53

What does it mean when it says to schedule the project?

Answer 53

Draw a scheduling diagram