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10. What is the difference between dependent and independent variables in regression?
Ans. In regression, the independent variable is the input or cause (like hours studied), and the dependent
variable is the result or outcome (like test score). The dependent variable depends on the independent one.

B. Long answer type questions.
1. What is an Entity-Relationship (ER) model? How is it useful in database design?

Ans. The ER model uses diagrams to show how different data items, called entities, are related. It includes
entities, their attributes, and the relationships between them. For example, a student enrolling in a course
taught by a teacher. It helps database designers plan the structure of the database clearly before creating
it.

2. List any four benefits of data modelling and explain how they help in system design.
Ans. Four benefits of data modelling are:
∑ ∑ Reduces errors in database design
∑ ∑ Improves communication between teams

∑ ∑ Increases performance of databases
∑ ∑ Helps organize data clearly
These benefits make it easier to create efficient systems that are reliable, easy to use, and meet the needs
of the business.
3. What is linear regression and how does it work?

Ans. Linear regression is a method used to find a straight-line relationship between two variables. One variable
is independent (input), and the other is dependent (output). The model creates a line of best fit using a
formula. This line helps us predict unknown values based on known data. For example, predicting marks
based on study hours.

4. How are regression coefficients useful in linear regression?
Ans. Regression coefficients include the slope and intercept of the regression line. The slope shows how much
the dependent variable changes when the independent variable increases. The intercept shows the value
of the dependent variable when the independent variable is zero. Together, they help create the regression
line and make accurate predictions.
5. Describe one real-life situation where you would use linear regression and explain why.
Ans. A business can use linear regression to predict monthly sales based on advertising spend. By analysing
past data, the company can draw a line showing how sales increase with more advertisement. This helps
in planning budgets and making better marketing decisions. It’s useful because it turns data into useful
predictions.

21 st
C. Competency-based questions: HOTS Century #Interdisciplinary
Skills
1. Meena collected data about students' study hours and their test scores. How can she use linear regression to
understand this data?

Ans. Meena can use simple linear regression to draw a line of best fit showing the relationship between study
hours (independent variable) and test scores (dependent variable). This will help her predict how much a
student might score based on how many hours they study.

2. While planning a hospital database, the IT team wants to show how patients, doctors, and treatments are
related. Which model will help them design this system and how?

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