Odds mean nothing to you
A thirty percent chance of rain and no idea what to do with it.
Courses
Start with three things you can do today
How to understand probability in everyday life
Judge chance and odds in real life, not just on dice.
A course on probability for everyday judgment. It covers what a probability actually is, how to combine chances, why rare things happen all the time, the traps that catch almost everyone, and how to use base rates and expected value to decide better.
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A starting goal
I want to understand probability well enough to judge odds, risk and chance in real life. Use everyday situations rather than dice and cards, and show me the common traps people fall into.
Change any word so it fits your situation. The course is built from what you type and a few setup questions.
Start today
Three things you can do before the course exists.
Useful on their own. The course is for when you want the whole skill, not just the first move.
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Name the event before interpreting the percentage
A US National Weather Service forecast of 30% precipitation concerns measurable rain or snow at a location during the stated period. It does not mean rain for 30% of the day. Read the location and time window first. Ask: what exactly could happen, and by when?
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Separate the chance from the consequence
In an invented planning example, suppose a 20% chance of delay would add 30 minutes; otherwise there is no delay. The average extra time is 0.20 times 30, or 6 minutes. A reliable alternative taking 4 extra minutes compares favorably on that measure. A hard deadline may matter more than the average.
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Check your answer before multiplying chances
Two independent deliveries each have an 80% chance of arriving on time. The chance both arrive on time is 0.8 times 0.8, or 64%; at least one is late with probability 36%. If both share a storm or carrier, independence may fail. Do not use that calculation without checking the assumption.
Sources: National Weather Service: interpreting precipitation probability; Open University: practice understanding risk. Practical examples are starting points, not promised results.
- Best for
- Math & numbers
- Prerequisites
- None. Bring the situation you have.
- Course length
- 7 to 30 lessons
- Pace
- Yours. One lesson at a time, as often as you like.
- Format
- Read it, or play the audio
- Access
- Available on the App Store and Google Play, with an optional early testing list
Before the course is built
Setup asks about your situation first.
Lesson 1 opens on the moment you describe, and the examples use your role. For this request, expect questions like these.
- Where does chance come up for you: health decisions, money, work forecasts, or just curiosity?
- How comfortable are you with fractions and percentages?
- Is there a specific kind of decision you want to think through better?
Right for now
If any of this sounds familiar, start here.
You are surprised by coincidences
It could not be chance, could it?
You want to decide better under uncertainty
Bets, insurance, medical tests, plans.
Course arc
Where the course goes, in order.
Cadence writes the lessons for you, so the exact path follows your answers. This is the ground a course built from this sentence covers.
01 / 06What a probability is
Percent, odds and frequency, translated.
Combining chances
Independence, and the common error that breaks everything.
Rare things happen
Why coincidences are expected, and lotteries are won.
Base rates
The test result, the rare disease, and the math people get wrong.
Expected value
A way to compare choices with uncertain outcomes.
The traps
Gambler's fallacy, hot hands, and the stories we tell about luck.
What changes
What you will be able to do, and what you will stop believing.
You will be able to
Know what probability means
Frequencies, beliefs, and why both matter.
Combine chances
And, or, and the mistake of multiplying what is not independent.
Use base rates
How prevalence and test accuracy affect the meaning of a positive result.
Decide with expected value
Weighing outcomes by their chances, and when not to.
Ideas this course corrects
After five heads, tails is due
For independent flips of a fair coin, earlier results do not change the next flip's one-half probability.
A one in a million event is impossible
Across many opportunities, a rare event becomes more plausible. The chance still depends on the number and relationship of those opportunities.
Course questions
What to know before you start.
How to understand probability in everyday life: what can I do today?
Name the event before interpreting the percentage. A US National Weather Service forecast of 30% precipitation concerns measurable rain or snow at a location during the stated period. It does not mean rain for 30% of the day. Read the location and time window first. Ask: what exactly could happen, and by when? Separate the chance from the consequence. In an invented planning example, suppose a 20% chance of delay would add 30 minutes; otherwise there is no delay. The average extra time is 0.20 times 30, or 6 minutes. A reliable alternative taking 4 extra minutes compares favorably on that measure. A hard deadline may matter more than the average. Check your answer before multiplying chances. Two independent deliveries each have an 80% chance of arriving on time. The chance both arrive on time is 0.8 times 0.8, or 64%; at least one is late with probability 36%. If both share a storm or carrier, independence may fail. Do not use that calculation without checking the assumption.
Is this a fixed course?
No. Cadence builds the course when you type the sentence and answer a few setup questions, so the lessons follow your situation. This page describes what a course built from this request covers. You see the whole path before Lesson 1.
Who is this course for?
A course on probability for everyday judgment. It covers what a probability actually is, how to combine chances, why rare things happen all the time, the traps that catch almost everyone, and how to use base rates and expected value to decide better. It sits under Math & numbers in the Ideas & discovery part of the library.
Do I need any prior experience?
No. Setup asks what you already know and where you want to use it, and the course starts from there. Bring a real situation if you have one; the examples are built around it.
How long does it take?
Most courses run 7 to 30 lessons. The course length is sized to what you asked for. You set the pace: one lesson at a time, as often as you like. Lessons can be read or played as audio.
Does this course award a certificate or degree?
No. Cadence is for practical self-learning and does not award accredited degrees or professional certification.
Start today
Type it, answer a few questions, open Lesson 1.
A starting goal
I want to understand probability well enough to judge odds, risk and chance in real life. Use everyday situations rather than dice and cards, and show me the common traps people fall into.
Want new features first?