Do you know the difference between a PDF & a CDF? #mathmethods #ia3 #probability

Added: 2026-05-26

[00:00:00]Do you know what the difference between a PDF and a CDF is? You can think of it like a rainstorm. The PDF, or probability density function, is like the density of rain at a specific moment. If the PDF is high, that means that it is pouring, and values around that point occur more often. Now, if the PDF is low, it is just a drizzle. Now, probability is not one exact value. It's about how much of the storm falls within a range. A short period of heavy rain adds lots of water. Now, a short period of light rain adds very little. So, when you measure the total rain collected over the interval, the total corresponds to the probability. That's why the area underneath the probability the density function gives us a probability.

[00:00:35]Now, the CDF, or the cumulative distribution function, is like the puddle forming on the ground. Instead of showing the rain intensity right now, it shows how much water has accumulated so far. That's why the CDF always increases. The puddle will always get deeper.

[00:00:49]And the Y value of the CDF directly gives probability. So, if the CDF is 0.6 at a 1.7, that means there is a 60% chance that the result is less than or equal to 1.7.

[00:01:00]So, while the PDF shows where the probability is concentrated, the CDF shows how the probability accumulates over time.