pairwise testing

Nel Nash-Hooks's picture

what kind of matrix is used for pairwise or all paris testing?

 

2 Answers

Chris Zidich's picture

I found that this website gives a good guide  https://controls.engin.umich.edu/wiki/index.php/Design_of_experiments_via_taguchi_methods:_orthogonal_arrays

here is my example 

So let’s have a look at this example,

We are testing a website for a car dealership

·         they sell 3 different types of vehicles

o   Hatch back

o   Sedan

o   Ute

·         Each vehicle type comes in 3 different Interior packages

o   Economy

o   Sports

o   Luxury 

·         Each vehicle type comes in 3 different Wheel packages

o   Steel wheels

o   Sports alloys

o   Luxury  18’ inch wheels

The company wants to know be assure that each combination of car type and package can be ordered from there website

Looking at the follow table we can easily workout which Orthogonal array is required for the example on the previous page In this case we need L9 as we have 3 parameters with 3 levels the next step is to replace the values in the table with the value of the Parameters and our levels Below is the array before replacing the values

Test

P1

P2

P3

P4

1

1

1

1

1

2

1

2

2

2

3

1

3

3

3

4

2

1

2

3

5

2

2

3

1

6

2

3

1

2

7

3

1

3

2

8

3

2

1

3

9

3

3

2

1

Now all we have to do is replace the values, as we only have 3 parameters the final column is removed

Test

Vehicle type

Interior package

Wheel Package

1

Hatch back

Economy

Steel wheels

2

Hatch back

Sports

Sports alloys

3

Hatch back

Luxury

Luxury 18s

4

Sedan

Economy

Sports alloys

5

Sedan

Sports

Luxury 18s

6

Sedan

Luxury

Steel wheels

7

Ute

Economy

Luxury 18s

8

Ute

Sports

Steel wheels

9

Ute

Luxury

Sports alloys

 

 

 

 

 

 

 

 

Note this doesn’t cover every possible combination but does cover all different pairs 

axshara s's picture
axshara s replied on April 21, 2014 - 1:02pm.

Allpairs.pl is a Perl script that constructs a reasonably small set of test cases that include all pairings of each value of each of a set of parameters. Actually, I don’t know if I’m saying that right. Let me show you. If you have two parameters you want to cover in a set of tests, say, printer and operating system, they might look something like this:

 

Operating System

Win98

Win2K

WinXP

 

Printer

HP 4050

 

HP 4100

 

All combinations of each of these parameters creates twelve test cases. But what if all we really need is a set of test cases that guarantee that each value of each parameter is paired in at least one case? Then we can get away with fewer cases. We’re back down to six 

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