Networks

Forward Pass – Max criterion – Si 2 tareas independientes son predecesoras de una tarea la ES de esta tarea corresponde a la mayor duración o duración +1 de la tarea predecesora con mayor duración.

Backward Pass – Min criterion – Si 2 tareas en backward pass dependen de una tarea predecesora el LF de la predecesora es la menor de las LS de las dependientes.

Distribución Beta es distribución PERT

Distribución triangular es similar a MEAN o AVG

Free Float = afecta ES de la siguiente actividad (ES-1)

Earned Value Management

SV = BCWP – BCWS = EV – PV

CV = BCWP – ACWP = EV – AC

VAC = BAC – EAC

CVP% = CV/BCWP = CV/EV

SVP%= SV/BCWS = SV/PV

CPI = BCWP/ACWP = EV/AC

SPI = BCWP/BCWS = EV/PV

EAC = (ACWP/BCWP) * BAC = (AC/EV) * BAC = BAC/CPI

ETC = EAC – ACWP = EAC – AC

EV = BCWP = (% complete) * BAC

% complete = BCWP/BAC = EV/BAC

% money spent = ACWP/BAC = AC/BAC

New project length = original length /CPI

Statistics

The mean is the average.

Example: Of the following numbers obtain mean 15, 18, 22, 20. The mean is (15+18+22+20)/4=18,75=>19.

The Median is the ‘middle value’ in your list. When the totals of the list are odd, the median is the middle entry in the list after sorting the list into increasing order.

When the totals of the list are even, the median is equal to the sum of the two middle (after sorting the list into increasing order) numbers divided by two. Thus, remember to line up your values, the middle number is the median! Be sure to remember the odd and even rule.

Example 1: Find the Median of: 9, 3, 44, 17, 15 (Odd amount of numbers)

Sort in ascending order: 3, 9, 15, 17, 44 The Median is: 15 (The number in the middle)

Example 2: Find the Median of: 8, 3, 44, 17, 12, 6 (Even amount of numbers)

Soft in ascending order: 3, 6, 8, 12, 17, 44 The Median is 10 = (8+12)/2

The mode in a list of numbers refers to the list of numbers that occur most frequently. A trick to remember this one is to remember that mode starts with the same first two letters that most does. Most frequently – Mode.

Example: Find the mode of: 9, 3, 3, 44, 17, 17, 44, 15, 15, 15, 27, 40, 8.

Put the numbers is ascending order: 3, 3, 8, 9, 15, 15, 15, 17, 17, 27, 40, 44, 44,

The Mode is 15 (15 occurs the most at 3 times).

Mode range is obtained by extracting from top high value the top low value.

In order to obtain Standard Deviation of some numbers you have to:

1. Obtain mean average of series.
2. Obtain variance.
3. Extract square root from variance.

Example: What is standard deviation for 80, 10, 50.

1. The average mean is 47 (m).
2. The variance is s²= (S(x-m)²)/n = (1089 – 74 + 9) / 3 = 339,3
3. Obtian √339,3 = 18,42.

(Pesimistic – Optimistic) / 6 = s

s_t=√s₁²+s₁²+s_n²+s_n+1²

Cost

Future Value = Present Value _{year 1}(1+ Investment Rate)^{year 1} + Present Value _{year 2}(1+ Investment Rate)^{year 2}+ Present Value _{year n}(1+ Investment Rate)^{year n}

Present Value = Future Value / (1 + Investment Rate)^{Number of Years}

NPV = [(NCF₁/(1+rate)^{year scalar 1})+ (NCF₂/(1+rate)^{year scalar2})+ …+(NCF_n/(1+rate)^{year scalar n})] – Initial Cost Investment

We have a project of 12 months (SAC).

At the end of month 6 we have:

• AC 10
• EV 14
• PV 17,5
• BAC 28

As you see the project is under budget but late. So to calculate the number of months it should take instead of 12 we shall:

TEAC = SAC/SPI, and if we are at the end of month 6 we should rest 6 months so (12/.8)-6=9 Months

We have a project of 12 months (SAC). We have

• AC 10
• EV 14
• PV 17,5
• BAC 28

As you see the project is under budget but late. So to calculate the amount of money it will cost to finish the project is

EAC = BAC/CPI –AC in our case it will be 28/1.4-10=10.