# Stats 116 will be replaced by Stats 117 and Stats 118

The Statistics Department is revamping the way it teaches introductory probability. After a careful review of the Stats 116 curriculum and student feedback, faculty determined that the amount of important content was challenging to cover effectively in a single 5-unit course.

Therefore, the department has decided to divide the content into two 3-unit courses: Stats 117 (Theory of Probability I) and Stats 118 (Theory of Probability II). By teaching the same material over two quarters, the content will be better paced, allowing students to absorb the material better and setting them up for success in later courses.

Stats 116 will be offered one last time in the autumn 2023 quarter. Stats 117 will be offered for the first time in spring 2024, with Stats 118 making its debut the following autumn. Full course descriptions are below:

- STATS 117: Theory of Probability I (3 units)

Introduction to probability theory, including probability axioms, conditional probability, independence, random variables, and expectation. Joint, marginal, and conditional distributions. Discrete models (binomial, hypergeometric, Poisson) and continuous models (normal, exponential). Prerequisites: Single-variable calculus including infinite series (e.g., MATH 21) and at least one MATH course at Stanford. May not be taken for credit by students with credit in STATS 116, CS 109, MATH 151, or MS&E 120. - STATS 118: Theory of Probability II (3 units)

Continuation of STATS 117, with a focus on probability topics useful for statistics. Sampling distributions of sums, means, variances, and order statistics of random variables. Convolutions, moment generating functions, and limit theorems. Probability distributions useful in statistics (gamma, beta, chi-square, t, multivariate normal). Prerequisites: a calculus-based first course in probability (such as STATS 117, CS 109, or MS&E 120) and multivariable calculus, including multiple integrals (MATH 52 or equivalent, can be taken concurrently). May not be taken for credit by students with credit in STATS 116.

## How will this affect program requirements?

- For the Data Science B.S., the first requirement of the statistics core will be fulfilled by any of the following options:
- Stats 116 (for students who take it in autumn 2023 or before)
- Stats 117
*and*Stats 118 - Math 151

- For the Data Science & Social Systems B.A., the first statistical inference requirement will be fulfilled by any of the following options:
- Stats 116 (for students who take it in autumn 2023 or before)
- Stats 117
- MS&E 120
- CS 109