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Bharath Prasad
Bharath Prasad

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Hypothesis Testing in Data Science – A Beginner’s Guide

In data science, we often face a question: “Is this change really working, or is it just random?” Hypothesis testing is a simple way to answer this using data and statistics.

What is Hypothesis Testing?
Imagine you own an online shop and change the checkout page design. Now, you want to know if sales have actually improved. Hypothesis testing helps check if this change is real or just by chance.

You start with two statements:

Null Hypothesis (H₀): No effect or difference

Alternative Hypothesis (H₁): There is an effect or difference

How It Works
State H₀ and H₁

Decide an error limit (usually 5%)

Choose the right statistical test – T-test, Z-test, Chi-square, or ANOVA

Collect clean and relevant data

Perform the test using tools like Python, R, or Excel

Compare the result with your error limit

Decide whether to accept or reject H₀

Where It’s Used
E-commerce: Testing product descriptions or designs

Education: Comparing test scores between two classes

Market Research: Checking survey relationships (e.g., gender vs buying preference)

Tips for Students
Match the correct test with your data type

Never rely only on numbers – think about the real-world meaning

Use it early in your analysis process

Hypothesis testing is like asking your data for proof before making a decision. In the tech world, it keeps your choices fact-based, not guess-based.

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