Error guessing involves asking "what if". For example, the 
statement might be made "the user must input a valid zip 
code". What if the user enters no zip code? What if the zip 
doesn't match the state? What if the zip code doesn't 
exist? Etc...

random condition data used for testing

Error Guessing comes with experience with the technology 
and the project. Error Guessing is the art of guessing 
where errors can be hidden. There are no specific tools
and techniques for this, but you can write test cases 
depending on the situation: Either when reading the 
functional documents or when you are testing and find an 
error that you have not documented.

Error guessing is a test case technique to check the 
application with invalid data,whether it is accepting the 
data or not
Murali
dharanmu@yahoo.com

Error guessing is a test case technique .if we r putting an 
invalid data to check the application.that our data 
accepting or not

Generating test cases against to the specification.

It is a black box testing technique. An experienced person 
can guess the error. Sometimes there can be some hidden 
errors.Without experience we can't find out it. If the 
tester is an experienced guy, when the situation saw, he 
can assume there is a chance to see some hidden 
errors.Without experience, no one can assume like this.

If it is wrong please correct me.

error guessing is a technique to guess differnt errors(yet 
to discover) by navigating the application  assuming from 
previous experience of simillar type of application.

it comes out of experience. it's just viewing the software 
with specifications and finding out the bug.

Error Guessing comes with experience with the technology 
and the project. Error Guessing is the art of guessing 
where errors can be hidden. There are no specific tools
and techniques for this, but you can write test cases 
depending on the situation: Either when reading the 
functional documents or when you are testing and find an 
error that you have not documented

Error Guessing is a test case design technique where the 
tester has to guess what faults might occur and to design 
the tests to represent them.

A test design technique where the experience of the tester
is used to
anticipate what defects might be present in the component or
system under test as a result
of errors made, and to design tests specifically to expose them.

Based on my Experience i know the errors

Error Guessing is a software testing design technique based 
on the ability of the tester to draw on his past 
experience, knowledge and intuition to predict where bugs 
will be found in the software under test.

Error Guessing mainly depends on the experience of the 
tester. It helps the tester to identify the error in prior, 
to identify the test cases on the basis of guessed errors 
in particular piece of software code.
The purpose of error guessing is to focus the testing 
activity on areas that have not been handled by the other 
more formal techniques, such as equivalence partitioning 
and boundary value analysis.  Error guessing is the process 
of making an educated guess as to other types of areas to 
be tested.  For example, educated guesses can be based on 
items such as metrics from past testing experiences, or the 
tester's identification of situations in the Functional 
Design Specification or Detailed Design Specification, that 
are not addressed clearly