Thursday, December 01, 2005

What is continous and discrete data?

So i had this basic doubt today of what is continous and discrete data :) , funny but I googled it to find

Stolen from isixsigma.com

Discrete Data :
Discrete data is information that can be categorized into a classification. Discrete data is based on counts. Only a finite number of values is possible, and the values cannot be subdivided meaningfully. For example, the number of parts damaged in shipment.

Attribute data (aka Discrete data) is data that can't be broken down into a smaller unit and add additional meaning. It is typically things counted in whole numbers. There is no such thing as 'half a defect.' Population data is attribute because you are generally counting people and putting them into various catagories (i.e. you are counting their 'attributes'). I know, you were about to ask about the '2.4 kids' statistic when they talk about average house holds. But that actually illustrates my point. Who ever heard of .4 of a person. It doesn't really add addition 'meaning' to the description.

Continous Data:
ontinuous data is information that can be measured on a continuum or scale. Continuous data can have almost any numeric value and can be meaningfully subdivided into finer and finer increments, depending upon the precision of the measurement system.

As opposed to discrete data like good or bad, off or on, etc., continuous data can be recorded at many different points (length, size, width, time, temperature, cost, etc.).

Continuous data is data that can be measured and broken down into smaller parts and still have meaning. Money, temperature and time are continous.Volume (like volume of water or air) and size are continuous data.

Let's say you are measuring the size of a marble. To be within specification, the marble must be at least 25mm but no bigger than 27mm. If you measure and simply count the number of marbles that are out of spec (good vs bad) you are collecting attribute data. However, if you are actually measuring each marble and recording the size (i.e 25.2mm, 26.1mm, 27.5mm, etc) that's continuous data, and you actually get more information about what you're measuring from continuous data than from attribute data.

Data can be continuous in the geometry or continuous in the range of values. The range of values for a particular data item has a minimum and a maximum value. Continuous data can be any value in between.

It is the data that can be measured on a scale.

-Kalyan

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