The document discusses decision trees and tables. It defines a decision tree as a graphical representation of possible solutions to a decision based on certain conditions. Decision trees show each decision sequentially and provide for random elements. Decision trees and tables are often used by businesses to plan strategies and analyze research. Decision tables specify actions to perform depending on given conditions and can be represented as decision trees or code. The advantages of decision trees and tables include being easy to understand, useful for data exploration, and formalizing the brainstorming process to identify more solutions. The limitations include overfitting and not fitting continuous variables.

1. DECISION TREES AND TABLES
Divya Sure
17MIS7054

2. What is decision tree?
• A decision tree is a graphical representation of possible solutions
to a decision based on certain conditions.
• Decision tree requires a systematic, documented thought process.
• Decision trees shows each decision sequentially.
• Provides for randow elements for business conditions that will be
related in future.

3. Decision tree in various sectors:
• Decision tree diagrams are often used by businesses to plan a
strategy, analyze research, and come to conclusions.
• Lenders and banks use decision trees to calculate the riskiness
of loans and investment opportunities.

4. Elements of decision tree
indicates condition
indicates an action

5. Limitations for Decision Tree:
• The biggest limitation of our decision making is that we
can only selecting from the known alternatives
• Provide less information of the relationship

6. Advantages:
• Easy to Understand
• Useful in Data exploration
• Less data cleaning required.
• Data type is not a constant.
• Decision trees help formalize the brainstorming process so we
can identify more potential solutions.
• The advantages of a decision tree are fairly obvious: a “path”
through possibilities, with alternatives, leading toward a desirable
outcome.

7. Disadvantages:
• Over fitting
• Not fit for continous variables.
• Loss of innovation-only past experience go into the branching
of choices, new ideas donot get much consideration

8. Example:
if student got marks >=90 percent
then
allot first category
else if
student got marks >=80 percent
then
allot second category
else if
student got marks>=50 percent&&<80
then
allot third category
else
No admission
end if
else
go to third category
end if
end if

10. Decision Tables:
• Decision tables are visual representation for specifying which
actions to perform depending on given conditions.
• Information in decision tables could also be represented as
decision trees or in a programming language as a series of if-
then-else and switch-case statements.

11. Why use decision tables?
• Powerful visualization
• Preventing errors is easier

12. Advantages:
• A decision table may be easier to construct than a flowchart.
• It is possible to check that all test combinations have been
considered.
• The tables show cause and effect relationships.
• They use standardized format.
• Easily understood making it very effective for communication
between analysts or programmers and non-technical users.

13. Disadvantages:
• The total sequence is not clearly shown, i.e., no overall picture
is given by decision tables as presented by flowcharts.
• Where the logic of a system is simple, flowcharts nearly always
serve the purpose better than a decision table.

14. Steps to draw decision table:
1.Analyze the requirement and create the first coloumn.
2.Add coloumn
3.Reduce the table.
Mark insignificant values with”-”.
4.Determine actions
5.Write test cases

15. Conditio
ns
Rule 1 Rule 2 Rule 3 Rule 4 Rule 5 Rule 6 Rule 7 Rule 8
marks>=
90percen
t
N N N N T T T T
marks>=
80percen
t
N N T T - - - -
marks>=
50%&&<
80%
N T - - - - - -
Actions
First
Category
- - - - X X X X
Second
Category
- - X X - - - -
Third
Category
-ss X - - - - - -
No
admissio
n
X - - - - - - -

16. References:
• https://www.slideshare.net/DMANIMALA/decision-table-44548879
• http://www.answers.com/Q/What_are_advantages_and_disadvantages_of_d
ecision_tables
• https://www.coursehero.com/file/p4bc0fm/What-are-the-Advantages-of-
Decision-Tables-1-This-type-of-testing-also-works/
• http://tryqa.com/what-is-decision-table-in-software-testing/
• https://en.wikipedia.org/wiki/Decision_table
• https://study.com/academy/lesson/what-is-a-decision-tree-examples-
advantages-role-in-management.html
• https://en.wikipedia.org/wiki/Decision_tree
• https://www.analyticsvidhya.com/blog/2016/04/complete-tutorial-tree-based-
modeling-scratch-in-python/

17. • https://www.kaggle.com/dmilla/introduction-to-decision-
trees-titanic-dataset
• https://gormanalysis.com/decision-trees/

18. THANK YOU