class_09_03

# class_09_03 - Statistical Data Mining ORIE 474 Fall 2007...

This preview shows pages 1–7. Sign up to view the full content.

Statistical Data Mining ORIE 474 Fall 2007 Tatiyana V. Apanasovich 09/03/07 Visualizing Data

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
3. Visualizing and Exploring Data Summarizing Data Tools for Displaying Single variables Relationships between two variables More than two variables Principal Component Analysis
3.2 Summarizing Data Suppose that x(1),…,x(n) is a set of n data values Relevant sample statistics are: Location measures: Mean Median and Quartiles Mode Dispersion or variability measures: Standard deviation and variance Interquartile range and range Skewness

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
3.2 Summarizing Data (cont’d) Ex: 100 data points sampled from a normal distribution with mean 0 and std. dev. 10
Sample Mean Sample Mean: Ex: (whereas µ=0) Location measure Sample mean is the value that is “central” in the sense that it minimizes the sum of squared differences between it and the data: Proof: = i i x n ) ( 1 ˆ μ 36 . 1 ˆ = μ ( 29 ( 29 = = - = - = - i i i i i x n a na i x a i x da a i x d ) ( 1 0 ) ( ) ( 2 ) ( 2 ( 29 2 ) ( min ˆ - = i a a i x μ

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Sample Median and Mode Sample median = value that has an equal number of data points above or below it If, as in our example, n is even, it is usually defined as the halfway between the 2 middle values Ex: (whereas m=0)
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern