STAT1051_lesson4-1

# STAT1051_lesson4-1 - Descriptive Statistics Numerical...

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

Descriptive Statistics Numerical Summary

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

View Full Document
2 Summation Notation Observations in a dataset are denoted by { x 1 ,x 2 ,x 3 ,x 4 ,.... x n }; n = sample size x 1 is the first observation, x 2 is 2nd obs. and so on. We use ∑ x i to denote x 1 + x 2 + x 3 + x 4 +.…+ x n In particular, n n i i x x x x + + + = = ...... 2 1 1
3 Example 5.0 Suppose a dataset contains obs . {3.5,11.2,8,.4,5.4}, Then n=5 , and 28.5 5.4 .4 8 11.2 3.5 = + + + + = + + + + = = 5 4 3 2 1 5 1 x x x x x x i i 231.01 5.4 .4 8 11.2 3.5 2 2 2 2 2 = + + + + = + + + = = 2 5 2 2 2 1 5 1 2 .. x x x x i i 812.25 28.5) 2 2 = = = ( ) ( 5 1 i i x Not Same

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

View Full Document
4 Population and Sample POPULATION Collection of all the units that we are interested in studying. SAMPLE A subset of the units of the population.
5 Numerical Summary Want to summarize the data using numerical descriptive measures. Two quantities to measure: I. CENTER Measure of central tendency II. VARIABILITY Spread of the data Both population and sample data can be summarized.

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

View Full Document
6 Central Tendency We want to locate the center of the data in three ways MEAN MEDIAN MODE
This is the end of the preview. Sign up to access the rest of the document.

## This note was uploaded on 11/27/2011 for the course STAT 1051-10 taught by Professor Balaji during the Fall '11 term at GWU.

### Page1 / 16

STAT1051_lesson4-1 - Descriptive Statistics Numerical...

This preview shows document pages 1 - 7. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online