This slides are about how to collect and analyze data

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INPUT DATA COLLECTION AND
ANALYSIS
Senir Justin
BITF20M550

2. Introduction
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Input data includes gathering, studying, and utilizing input data
in the simulation method
The collection may be gathered from any source.
 A study of input data shows the theoretical distribution of data
the practitioner only gathers a sample of the actual data
distribution when collecting data..

3. Collecting Input Data
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There are many ways to collect input data like the following:
 Historical records
 Manufacturer specifications
 Vendor claims
 Operator estimates
 Management estimates
 Automatic data capture
 Direct observation

4. Collecting Input Data
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 Input data may be collected manually or with the assistance of
electronic devices
 It is the most difficult part of the simulation process
 While colleting input data, there are different classifications of data

5. Classification of Data
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There are two methods for the classification of data:
 Deterministic or probabilistic
 Discrete or continuous

6. Deterministic /Probabilistic Data
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Deterministic Data
 Deterministic data are those in which the event affecting the
data occurs consistently or predictably.
Probabilistic Input Data
 A probabilistic process does not occur with the same type of
regularity.
 This implies that since the value of this type of data never
changes, it only has to be gathered once.

7. Discrete/Continuous Data
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Discrete Data
 It can take only certain values. Usually, this means a whole number.
 The number of students in class is an example
Continuous Data
 It can take any value in the observed range. This means that
fractional numbers are a definite possibility
 Height of children is an example

8. Input Data Distributions
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Bernoulli Distribution:
 Models a random occurrence with one of two possible
outcomes
 Frequently referred to as a success or failure
Uniform Distribution:
 It can be used as a first cut for modeling the input data
 It may be either discrete or continuous
Exponential Distribution :
 Commonly utilized in conjunction with interarrival processes
 Random no. of entities will arrive within a specific time

9. Input Data Distributions
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Triangle Distribution:
 Used in situations where the practitioner does not have complete
knowledge about the system
 It has only three parameters:
i) Minimum Possible Value
ii) Most Common Value
iii) Maximum Possible Value

10. Less Common Distributions
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Geometric distributions:
The geometric distribution gives the probability of achieving success after
N number of failures
 It is discrete which means that distribution must be whole number
Weibull Distribution:
The Weibull distribution is often used to represent distributions that cannot
have values less than zero
 It has two parameters

11. Analyzing Input Data
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Graphics Approach:
Graphic approach is the most fundamental approach to attempting to fit
input data
 It consists of visual qualitative comparison between actual and
theoretical data distribution
Chi-Square:
The chi-square test is based on the comparison of the actual number of
observations
versus the expected number of observations
Commonly accepted as preferred goodness fit technique
Kolmogorov–Smirnov:
The KS test should be utilized only when the number of data points is

12. Software Implementations for
Data Fitting
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 Fitting a significant no. of observed data sets to theoretical
distributions is a time consuming task
 For this purpose, practitioners use data-fitting software
 The following two are frequently used to carry out this function:
1. Arena input analyzer
2. Expert fit

13. Arena input analyzer
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 Input analyzer is part of ARENA simulation software package
available from Rockwell software
 It has the capability to:
1. Determine the quality of fit of probability distribution functions to
input data
2. Examine a total of 15 distributions for data fitting
3. Calculate Chi-square, KS and square error tests
4. Generate high-quality data plots

14. Expert Fit
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 This software is available through Averil M. Law & Associates
 This software has the capability to:
1. Automatically determine best probability distribution for data
sets
2. Fits 40 distributions
3. Conduct Chi-sqaure, KS and Anderson-Darling goodness of fit
tests
4. Provide high-quality plots
5. Analyze a large no. of data sets in batch mode

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