Lecture 1 PDF

Preview

Summary

LEcture 1 slides...

Description

MA 213: Basic Statistics & Probability Instructors: Solesne Bourguin & Ting Zhang Class Introduction

Class Logistics  Lecture: Tuesday, Thursday 12:30pm-1:45 pm  Everyone together, slides and chalkboard talks  Lab/Studio: Once a week – check your schedule  Work in small groups, practice collecting and analyzing data  Discussion: Once a week – check your schedule  Answer questions and work through examples in small class

MA 213

2

Class Textbook Statistics, 13/E James T. McClave, Terry Sincich

ISBN-10: 0134080211 ISBN-13: 9780134080215

Publisher: Pearson

MA 213

3

Clickers - ResponseWare 

Purchase clickers at BU Bookstore - App on Android/Apple store



Bring to every lecture and lab/studio session



We will use these :





To poll the class during lecture,



To test your comprehension,



To collect data to analyze in lab.

Extra credit for correct answers, and answering all questions (make sure batteries are charged). MA 213

4

Clickers 

100%

Example question:

Did you bring your clicker to class today? 1. 2. 3.

Yes No What’s going on, I wasn’t paying attention Yes

MA 213

0%

0%

No

What’s going on, I wasn’t paying attention 5

Collecting data with clickers  1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

Pick a random number from 1-10:

1 2 3 4 5 6 7 8 9 10

20% 15% 10%

15%

10%10%10% 5%

5%

0% 1 MA 213

2

3

4

5

6

7

8

9

10 6

Collecting data with clickers  1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

Pick another random number from 1-10 (Try for uniform):

1 2 3 4 5 6 7 8 9 10

0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 1

2

MA 213

3

4

5

6

7

8

9

10 7

Lab/studio sessions 

You will analyze data using the JMP software package.



Always read pre-lab in advance and answer questions



Work in small groups of 5-6



Take quiz on Blackboard about in-lab and post-lab activities

MA 213

8

Course Webpage 

Blackboard site



Logging on: 

Go to http://learn.bu.edu and login with your kerberos name and password



What’s there: 

Announcements, Lecture slides, Assignments, Surveys…



Discussion boards: Ask questions about class materials, Answer questions…

MA 213

9

Course Webpage 

Your first assignment (on Blackboard): 

Logon and complete the online survey in the assignments tab



Due: Thursday 09/06



No wrong answers!

MA 213

10

Assignments 

Weekly problem sets (25% of grade)



Exams – Midterm (20%) and Final (30%)



Project – Milestones, presentation, and report (25%)



Extra Credit opportunities: 

Clicker questions

MA 213

11

Project 

Goal: Put the methods you learn into practice.



Steps: 1.

Select an area of interest and formulate questions

2.

Design your study

3.

Collect the data

4.

Perform statistical analyses

5.

Write up project report and present your findings to the class MA 213

12

Project Example Suppose we wanted to conduct a study to understand the coffee drinking habits of BU students…

MA 213

13

Project Example: Questions Suppose we wanted to conduct a study to understand the coffee drinking habits of BU students

•

How much coffee does a BU student drink per day on average?

•

Is coffee drinking associated to an activity – say, studying – or time of the day?

•

Is there a difference in coffee drinking habits between freshmen and seniors, or across majors?

•

Is drinking too much coffee bad for you? MA 213

14

Study design: collecting data To answer our questions, we need data; but how do we collect it?

•

Sources:

MA 213

15

Study design: collecting data To answer our questions, we need data; but how do we collect it?

•

Sources:

•

Published source: e.g. Journal article about student coffee intake and risks.

•

Surveys or polls: e.g. Ask sample of students about their coffee drinking habits.

•

Designed experiment: e.g. Break students into groups with different doses and evaluate health/performance.

•

Observational study: e.g. Record coffee intake and other data from a student sample, without influencing their actions. MA 213

16

Study design: how much data?  We are interested in habits of all BU students, but it’s often difficult to collect data for our entire population of interest…  We can use a smaller, representative subset of the population: a sample  But different samples can yield different data and thus different conclusions… how to account for the uncertainty?  Why might the set of MA 213 students not be a representative sample? MA 213

17

Study design: types of data Our analysis of the data will depend on its type

•

Qualitative (nominal) data are measurements that cannot be recorded on a natural numerical scale, but are recorded in categories.

•

Quantitative data are measurements that are recorded on a naturally occurring numerical scale

•

Ordinal data uses numerical values to assign an order to the possible values, but not a relative scale.

•

Continuous (Interval) data uses numerical values to express the value and relative scale of the data. MA 213

18

Collect data: Example poll questions 1.

How many cups of coffee per day you drink per day, on average?

2.

I drink (or would consider drinking) coffee mostly because…

3.



It tastes good



It keeps me awake, more alert



I like the coffeehouse crowd



Other reason

How much do you enjoy the taste of coffee on a scale from 1 (bad) to 5 (excellent).

4.

I would be less likely to drink coffee if I were shown a study about its negative health impact (yes/no) MA 213

19

Collect data: question 1 How many cups of coffee do you drink per day, on average? 1. 2. 3. 4. 5. 6. 7.

One Two Three Four Five More than five Zero

48%

29% 14% 5%

5% 0%

MA 213

0%

20

Collect data: question 2 I drink (or would consider drinking) coffee mostly because… 1. 2. 3. 4.

It tastes good It keeps me awake, more alert I like the coffeehouse crowd Other reason

69%

15%

12% 4%

1. MA 213

2.

3.

4. 21

Collect data: question 3 How much do you enjoy the taste of coffee on a scale from 1 (Bad) to 5 (Excellent)? 28% 1. 2. 3. 4. 5.

Bad Fair Good Very good Excellent

28%

20% 16% 8%

MA 213

22

Collect data: question 4 I would be less likely to drink coffee if I were shown a study about its negative health impact (yes/no) 1. 2.

Yes No

57% 43%

Yes MA 213

No 23

Project: Statistical analysis 

Once we collect the data, what can we do with it?

• Visualize it

• Build models

• Summarize it

• Make predictions

• Describe specific features

• Test a hypothesis

MA 213

24

Project: Statistical analysis 

We can now use the collected data to describe our sample and make inference on our population



Descriptive statistics: utilizes numerical and graphical methods to look for patterns and summarize a dataset



Inferential statistics: utilizes sample data to make estimates, decisions, predictions or other generalizations about a larger set of data MA 213

25

Project: Statistical analysis Some descriptive statistical statements 

A sample of BU students drank an average of 1.7 cups of coffee per day



95% of students in the sample drank between 0-4 cups per day



Students in the sample who visited the health center for insomnia drank an average of 2.1 cups of coffee per day.



Boxplots:

Cups



MA 213

Statistical analysis: descriptive stats

MA 213

27

Project: Statistical analysis 

An example of statistical inference



From the data, we are 95% confident that the average number of cups of coffee drank by the population of BU students is between 1.5 and 1.9.

MA 213

Statistical analysis: inferential stats

MA 213

29

Sample, Population, and Statistics

Probability Population

Sample

Descriptive Statistics

Sample

Inferential Statistics

MA 213

30

Your Statistical Project 

In this course you will be conducting a statistical investigation on a topic of your interest!



Projects will be created and worked on by the same lab session groups; check your group at Blackboard



Groups will deliver a final written report and present their results to the class



You can start thinking about the concepts and ideas discussed today: what questions would you like to answer about your topic, how would you collect, summarize, and analyze data… MA 213

31

Next Time 

Methods for visualizing qualitative and quantitative data.



Reading:





Chapter 1, pages 2-18



Section 2.1 – 2.3, pages 30-60.

Your first homework assignment: 

Logon and complete the online survey in the assignments tab



Due: Thursday 09/06



No wrong answers!

MA 213...