STAT 17: Statistical Methods for Business and Economics

Prof. Marcela Alfaro Cordoba

Statistics - UCSC

01 Sep 2025

The $15 Million Algorithm

In 2006, Netflix offered a $1 million prize for improving their recommendation algorithm by just 10%

The result? Better recommendations led to $15+ million in annual savings from reduced customer churn

The tool? Statistics and data analysis

Every Decision is a Statistical Decision

• Business: Should we launch this product? → Market research & hypothesis testing
• Economics: Will raising minimum wage hurt employment? → Regression analysis
• Personal: Which job offer should I take? → Expected value calculations
• Investment: Is this stock undervalued? → Probability distributions

Every Decision is a Statistical Decision

You’re not just learning formulas—you’re developing a superpower for life: the ability to make decisions with confidence in an uncertain world.

Why Statistics Matter for YOUR Future

💼 Business Leaders

• 73% of executives say data-driven decision making is critical.
• Companies like Google, Amazon, Apple: built on statistical insights
• AI? also runs on statistical insights - and understanding statistics is important to understand the uses and limitations of the new products.

🧠 Problem-Solving Skills

• Critical thinking: Question assumptions, evaluate evidence
• Pattern recognition: See trends others miss
  
• Risk assessment: Make better decisions under uncertainty
• Communication: Present compelling, data-backed arguments

🚀 Your Competitive Edge

In any field—marketing, finance, consulting, entrepreneurship, policy—you’ll be the person who can turn data into actionable insights

Meet Your Teaching Team 👋

Your instructor

Prof. Marcela Alfaro Cordoba
Associate Professor of Teaching - Statistics
Stats & Data Science Educator and Education researcher
Applied statistician (environmental & biological problems)

• 🍃 10+ years teaching statistics
• Background: Statistical & Data Science Education + Applied Stats
• Originally from Costa Rica 🌊
• Pronunciation: [mahr-sahl-ah]

R programming
stats
data visualization
data science
open and reproducible science

Office Hours: Tuesdays & Thursdays 5:00-5:30 PM (right after class!) + Thursday online appointments I’m here to help you succeed—use these hours!

Your Teaching Assistants

Seokjun Choi
PhD Candidate
Sections B & F
schoi90@ucsc.edu

Xiao Zhang
PhD Student
Sections A & C
xzhan481@ucsc.edu

Samantha Zhu
PhD Student
Sections D & E
sabzhu@ucsc.edu

+ Learning Support Services Tutors: Sadhika Agrawal & Sharry Eydel
+ Readers: Misha Tran Burton, Ingrid Eliza Fowler-White, Sadhika Agrawal

Your turn!

• First, introduce yourself to at least 3 of your neighbors.
• Then, if you haven’t, go to Canvas and check all Week 0
• Complete Survey 1 and the syllabus acknowledgement.

LSS Successful Slug Workshop

Materials for the workshop

Course Essentials 📋

Canvas

Required Materials

📚 Textbook (FREE!)

Introduction to Business Statistics
OpenStax, 2nd Edition

openstax.org/details/books/introductory-business-statistics-2e

💻 Technology

• Laptop/desktop computer
• Google Suite access
• Poll Everywhere (I’ll cover the cost!)

📍 Class Logistics

When: T/Th 3:20-4:55 PM
Where: Media Theater M110
Lab: STAT 17L (concurrent enrollment required)

Communication:
1. Ed Discussion (best option!)
2. Email (2-3 day response time)

Grade Breakdown

Component	Percentage	Details
Final Exam	30%	Dec 10, 4-7 PM
Midterm Exam	25%	Oct 30 (in class)
Worksheets	20%	7 total, drop 2 lowest
Homework	10%	7 total, drop 2 lowest
Participation	10%	Attendance + engagement
Exam Wrapper	5%	Reflection assignment

Grade Breakdown

Grade Scale

Letter	Score	Letter	Score
A+	x ≥ 99	C+	70 ≤ x < 74.99
A	95 ≤ x < 98.99	C	65 ≤ x < 69.99
A-	90 ≤ x < 94.99	C-	60 ≤ x < 64.99
B+	85 ≤ x < 89.99	D	50 ≤ x < 59.99
B	80 ≤ x < 84.99	F	x < 50
B-	75 ≤ x < 79.99	P/NP	x ≥ 65 / x < 65

The Rules That Matter Most

✅ Attendance & Flexibility

• 3 absence tokens per quarter
• Fill out token form by end of day
• Discussion sections mandatory for worksheet credit
• All exams in-person only

📝 Assignments

• Homework: completion-based, 1 week to complete
• Worksheets: pair work in discussion sections
• Late penalty: -1 point per day. Closed after 1 day.

The Rules That Matter Most

🤖 AI Policy

For studying: ✅ Create practice problems, explain concepts
For graded work: ❌ No AI assistance on homework, worksheets, exams

Why? You need to build these neural pathways yourself!

🎯 Success Tips

• Read textbook weekly
• Attend office hours early & often
  
• Form study groups
• Build formula sheets as you go

Academic Integrity

What’s Expected

• Submit your own work on all graded assignments
• Proper citations when using external sources
  
• No sharing of exam content
• Ask questions if you’re unsure about the rules

What’s Not Allowed

• Using AI tools for homework/worksheets/exams
• Copying from classmates or online sources
• Sharing exam questions with future students
• Self-plagiarism from other courses

What You’ll Master This Quarter

1. Describe data effectively → Tell compelling stories with numbers
2. Understand probability → Make decisions under uncertainty
   
3. Master sampling & estimation → Draw conclusions from limited data
4. Hypothesis testing → Prove your points with statistical evidence
5. Regression analysis → Predict and understand relationships
6. Real-world applications → Solve actual business & economics problems

Tools: Google Sheets (in class) + STATA (in STAT 17L) <- separate course

Let’s Get Started! 🚀

Your First Week

This Week’s Goals:

• Access the free textbook
• Join Ed Discussion (link on Canvas)
• Complete Survey 1 and syllabus acknowledgement
• Attend your discussion section (sections start tomorrow!) and submit WS1
• Read Chapter 1: “Sampling and Data”

Discussion Sections (Start tomorrow!)

Section	Day/Time	Location	TA
01D	Fri 2:40-3:45 PM	Physical Sciences 140	Samantha
01E	Fri 4:00-5:05 PM	Physical Sciences 140	Samantha
01A	Mon 8:00-9:05 AM	Earth & Marine B210	Xiao
01B	Mon 9:20-10:25 AM	Porter Academic 144	Seokjun
01C	Tue 7:10-8:15 PM	Earth & Marine B210	Xiao
01F	Thu 8:00-9:05 AM	Physical Sciences 110	Seokjun

Let’s test Poll Everywhere

Write ONE word you relate with statistics

Final Thoughts

You’re about to develop one of the most valuable skill sets of the 21st century

• Statistics isn’t just math—it’s critical thinking with numbers
• Every successful business leader, policy maker, and researcher relies on these skills
• You’ll leave this class seeing the world differently: questioning assumptions, demanding evidence, making better decisions

Final Thoughts

Ready to unlock the power of data? Let’s begin this journey together!

Questions? Office hours start next week, or catch me after class today.

Welcome to STAT 17!

Let’s make some data-driven magic happen this quarter ✨