Understanding the World with Data

STAT 20: Introduction to Probability and Statistics

Agenda

• Introductions
• The Data Science Lifecycle
• Types of Claims with Practice
• Course Structure
• Looking forward

Introductions

• Let us first introduce ourselves!

Introductions

• In groups of 3, take turns introducing yourselves to one another by providing the info listed on the worksheet (your name, hometown, etc).

• Each person should finish with a worksheet filled-in with info on their groupmates. Make sure you save this for later this week!

05:00

The Data Science Lifecycle

What’s going on here?

• As a group, formulate at least three possible explanations for what’s going on in the picture.

03:00

These three photos were taken in quick succession by a physician and amateur photographer who was vising the San Diego Zoo Safari Park. He was watching the shoebill as it was walking down a path in the reeds. As the shoebill was ambling along, it encountered a duck in the middle of the path. It leaned down, picked up the duck in its beak, turned to the side, dropped the duck in the reeds, then proceeded to amble down the path.

Understand
the World

Data

Understand
the World

Data

Takeaways from this exercise

We can call the process of:

• having a question,

• finding data to investigate that question,

• reaching a conclusion,

• and then thinking of a next step which starts everything over again

• the data science lifecycle.

This lifecycle involves constructing and critiquing claims made using data: which is the main goal of our course!

Types of Claims

Course Goal

To learn to critique and construct
claims made using data.

To learn to critique and construct
claims made using data.

To learn to critique and construct
claims made using data.

To learn to critique and construct
claims made using data.

To learn to critique and construct
claims made using data.

To learn to critique and construct
claims made using data.

To learn to critique and construct
claims made using data.

A numerical, graphical, or verbal description of an aspect of data that is on hand.

Example
Using data from the Stat 20 class survey, the proportion of respondents to the survey who reported having no experience writing computer code is 70%.

A numerical, graphical, or verbal description of a broader set of units than those on which data was been recorded.

Example
Using data from the Stat 20 class survey, the proportion of Berkeley students who have no experience writing computer code is 70%.

A claim that changing the value of one variable will influence the value of another variable.

Example
Data from a randomized controlled experiment shows that taking a new antibiotic eliminates more than 99% of bacterial infections.

A guess about the value of an unknown variable, based on other known variables.

Example
Based on reading the news and the price of Uber’s stock today, I predict that Uber’s stock price will go up 1.2% tomorrow.

Your turn!

• Flip over your worksheet and answer the questions!

05:00

Break

05:00

Course Structure

A fair concern

“Does flipped classroom just mean
I have to do more work?”

In a typical class…

In class

The instructor explains.

You listen.

At home

You try to use it.

You do the work.

The problem

The hardest part happens at home—
when nobody is there to help.

So we move the work

At home

Read the notes and tutorials.

Answer the reading questions.

Come prepared to begin.

In class

Solve problems.

Work on assignments.

Get help while you work.

The goal

You should usually be
DONE with your work
when you leave class!

Class is work time

Come prepared. Work hands-on. Ask questions.

We will be here to help—but you have to use the time.

If class becomes phone time, the whole system stops working.

General class logistics

tl;dr

Bookmark the course website now: https://stat20.berkeley.edu/fall-2026/

Seriously do these things (on the website):

1. Read the syllabus. It answers a lot.
2. Watch the video website tour. Also answers a lot of questions.

Everything on the next slides is already covered by the syllabus and video above.

Mondays (the 1-hour class)

• Attendance not required
• Each prof does it differently, but usually it’s just office hours.

Attendance (Wed/Fri only)

• 7% of your grade.
• You get a few free absences for illness or whatever comes up (see syllabus).

Attendance not tracked today, but in future W/F classes…

• As you walk into class, you’ll get a “warmup” handout on blue paper with some warmup problems.
• Write your name on it and start working with people at your table.
• We’ll review these questions at the start of lecture
• Near the end of class, we’ll collect these warmups and record the names as attendance.

Attendance (Wed/Fri only)

However:

• If you’re more than 5 minutes late to class, you won’t get a warmup sheet (and therefore won’t get attendance credit)
• If you leave early, we won’t take your warmup sheet (so no attendance credit)
  • Exception: if you finish all your work (worksheets and labs), show us. Then you can go!
  • This should be the norm for you.
• For special circumstances, approach your instructor.

Logistics - Reading and Assignments

1. Do readings before class: notes and tutorials
   • One small assignment due the day before every class: Reading Questions, completed directly on Gradescope
2. ALL assignments are submitted on Gradescope (see website)
   • For paper worksheets (like you got today), you’ll use your phone to “scan” them to pdfs before submission.
     • Don’t lose today’s worksheet yet - you’ll use it Friday
   • Worksheets are given out daily, so we have you submit them in batches “worksheet packets”
   • More on labs when we meet Friday

This is for you to speak through in your own words. Have the course website open in as you go. Point things out to them. But seriously, the syllabus and videos should be excellent orientation (if they do them)

Logistics - Quizzes and Retakes

1. Quizzes are done elsewhere (CBTF), and you have to sign up for a timeslot
   1. We’ll communicate more as they approach, but see syllabus and website for all the info you need.
2. You can retake each quiz once if you want
   • It’s a separate thing to sign up for, offered in the ~2 weeks after the initial quiz.
   • Retake score averaged with original score.
3. Capstone project coming later in semester, stand by for details

This is for you to speak through in your own words. Have the course website open in as you go. Point things out to them. But seriously, the syllabus and videos should be excellent orientation (if they do them)

Math diagnostic (ungraded, but informs us)

1. Everyone has holes in their math education.
2. We want to help everyone fill those holes so they can do well in Stat 20.
3. Therefore, now we do a math diagnostic test. It’s short. It’s not graded.
4. We’ll learn where the class, overall, is strong and weak.
5. We’ll soon share materials to help you fill the gaps you realize you have.
6. Again, this is to help you, not judge you or filter you out.
7. You can turn it in and leave when you’re done.

20:00