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Learn the basics of p-values and confidence intervals to make better data-driven decisions
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Educational content slides
Question: How many people needed in a room for 50% chance two people share a birthday?
Your intuition probably says: 183 people (half of 365 days)
Actual answer: Only 23 people!
With 50 people: 97% chance of shared birthday
Why this matters: Our brains are terrible at probability and randomness. We need mathematical tools (statistical significance) to know when patterns are real vs random noise.
This is why you can't trust your gut about whether test results are meaningful.
Test your understanding with this quiz.
A/B test with 1 million users shows new design increases clicks by 0.4%, p-value = 0.01. What can you conclude?
Complete this exercise and get AI-powered feedback.
Headlines love to claim studies 'prove' things. Now you know what questions to ask.
Think about: Sample size, p-values, confidence intervals, multiple testing, effect size, confounding variables.
This reveals: How to be a skeptical consumer of research claims and avoid being misled by bad statistics.