1. Language Describing Data by Tables and Graphics Chapter 1 (and 0)
Lectures 1-2 Week1
Language Describing Data by Tables and Graphics
Chapter 1 (and 0)
11/29/2018
Language

2. Language What is a variable? What is an Experimental Unit?
Example
What is an Experimental Unit?
What is a measurement (or data)?
What are sampling, sample, populations?
11/29/2018
Language

3. Why we need sampling Example1
record Body temperature for every healthy person on Earth!!!
Example2
Legislative preference in Canada
11/29/2018
Language

4. Data Univariate data Bivariate data Multivariate data Example
11/29/2018
Language

5. Descriptive and Inferential Statistics
Descriptive (sample)
Example
Inferential Statistics (Population)
11/29/2018
Language

6. Types of variables Qualitative ( or Categorical) Quantitative Examples
11/29/2018
Language

7. Two types of quantitative data
Discrete: Finitely many or countable values
Examples
Continuous: over an interval
11/29/2018
Language

8. Describing Categorical data by tables and graphs
Get the information:
What values have been measured
How often each value has occurred
Get tables or graphs as a summary
11/29/2018
Language

9. Graphical Tools Frequency Relative frequency Percent
Rules: Sum up to n, 1, 100% respectively.
11/29/2018
Language

10. Example1: Summarizing an Opinion Poll by a table
280 undergrad students polled, their opinion about a proposed change in dormitory regulations.
Choices are 3: Support, Oppose, Neutral.
Results: 152, 51, 77 respectively.
11/29/2018
Language

11. Example2 ( Using graphs)
400 school administrators have been surveyed to rate the quality of public education in USA. They ranked it using A,B,C, or D.
Pie chart
Bar chart
11/29/2018
Language

12. Describing Quantitative Data
Example1 The amount per category of money spent by US defense dept. in 2000
That is the Variable
X=“amount of money spent”
is measured for several categories
Draw a Pie chart for this data.
11/29/2018
Language

13. Quantitative (Cont’) Example2 (Time series)
When data are measured over equally spaced intervals of time.
line chart. Discern a pattern.
11/29/2018
Language

14. Quantitative(Cont’) Stem and Leaf plot Stem component Leaf component
11/29/2018
Language

15. Quantitative(Cont’) Frequency Histogram plot
The quantitative analogue of bar chart for qualitative
Example1 GPA
Example 2 airline
Example 3 Discrete (weekly number of litres of milk per family)
11/29/2018
Language

16. Graph shape Symmetric Skewed to the right or left
Unusual observations (outliers)
11/29/2018
Language