Harvard STAT 110: Introduction to Probability
Stat 110 is Joe Blitzstein's celebrated probability course, covering counting, conditional probability, random variables, distributions, expectation, and Markov chains. It's known for its storytelling style and brutal-but-beautiful problems, and its free lecture videos have made it a global staple for self-learners and quant-interview preppers.
Fennie is independent and not affiliated with Harvard University. This is an unofficial study guide.
What makes it hard
The lectures feel intuitive; the problems do not. Stat 110 psets demand creative problem-solving: choosing the right story, symmetry, or conditioning argument. Students who can follow every lecture still get stuck for hours on psets. Conditional probability and expectation tricks are the make-or-break skills.
What you'll cover
- • Counting and combinatorics
- • Conditional probability and Bayes' rule
- • Discrete and continuous random variables
- • Expectation, variance, and covariance
- • Joint distributions
- • Law of large numbers and CLT
- • Markov chains
The STAT 110 study guide
How to study for Harvard STAT 110, step by step.
- 1
Watch the lecture, then attempt problems immediately
Stat 110's lectures feel intuitive and the problems do not, and that gap is the course. Enrolled or using the free online lectures, never let a lecture pass without attempting related problems the same day.
- 2
Work the strategic practice problems by theme
The course's strategic practice sets group problems by technique: conditioning, symmetry, indicator variables. Working them theme by theme builds the pattern recognition the psets demand.
- 3
Learn every distribution as a story
Blitzstein teaches distributions through the scenarios that generate them, and that's how exam problems are recognized. For each named distribution, know its story, support, expectation, and variance cold.
- 4
Struggle honestly before checking solutions
For self-learners using the textbook's solved problems: give each one a real attempt, hours not minutes, before reading the solution. The struggle is where the problem-solving instinct gets built.
Today
Today's STAT 110 plan
What a Fennie Daily Plan looks like for STAT 110. Yours is built from your own syllabus and adapts every day to your deadlines and progress.
First plan free, no card required. Fennie is independent and unaffiliated with your school.
FAQ
Is Stat 110 hard?
Yes. The gap between understanding lectures and solving psets is famously large. Plan for serious weekly problem time; the difficulty is creativity, not computation.
Can I self-study Stat 110 online?
Yes. The full lectures are free online and the course textbook (Blitzstein & Hwang) with practice problems is widely available. It's one of the most-recommended probability resources for data science and quant prep.
What math do I need for Stat 110?
Solid single-variable calculus and comfort with summations; multivariable helps for joint distributions. The real prerequisite is willingness to struggle productively with problems.