MandysNotes

Wordy Definitions

Wordy Definitions (3)

Saturday, 23 January 2010 02:57

The Distribution of a Statistic

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{module [80]}The distribution of a statistic is officially called the sampling distribution of the statistic. 

Broken down a little bit further, the distribution of a statistic is all possible values of the statistic for samples of any given size.  Try not to get too crazed by all the fancy lingo when first starting out in a Stat course.  Check out our section on What's with the Greek? for more definitions broken down.

Friday, 22 January 2010 23:00

What is a Sample?

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A SAMPLE is a sub-set of the POPULATION.

A SAMPLE is drawn to represent the population, negating the need to conduct an extensive census. 

An example of a sample would be:

You decide you want to take a survey of the student body at your school.  Without a team of helpers, it will be nearly impossible to survey EVERYONE in a short period of time.  So instead, you decide to draw a SIMPLE RANDOM SAMPLE, which you determine is representative of the population. 

Studying and drawing CONCLUSIONS from a sample would be a heck of a lot easier than trying to survey every person (and study every person) in the Population

Friday, 22 January 2010 21:50

Population

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OK, so "population" doesn't exactly merit a "wordy definition" on its own.  But when we think of "population" we often think of the U.S. population - such as is recorded by the U.S. Census. 

 

 

This is not too far off-the-mark.  According to Wikipedia:  "A population can be defined as including all people or items with the characteristic one wishes to understand."

 

 

More simply put, a statistical POPULATION is the POOL from which a SAMPLE can be drawn. 

 

POPULATIONS can often be large, making studies overly complex, time-consuming and expensive.  This is why we draw a SAMPLE and go to great lengths to find a SAMPLE that is REPRESENTATIVE of the POPULATION.  This yields more time-efficient studies conducted on a SAMPLE instead of the entire POPULATION. 

NOTRad