General

ID #1000

What are variables? What are observations?

In Array Studio, a variable is a collection of single measurement from multiple subjects. A variable is a row in a dataset. So, for Affymetrix chips, a variable is a probeset or a SNP. An observation is a collection of a multiple measurements for a single subject. An observation is a column in a dataset. So, for Affymetrix chips, an observation is a single chip.
Array Studio allows the user to run analyses on specified variables and observations. So, if the user only wants to perform a specified analysis on a particular set of chips, or a particular set of probesets, they can do this by specifying a variable list, or an observation list. There are also options to allow running the module on (all) variables or observations, (selected) variables or observations, or (visible) variables or observations.
In the View Controller, the Variables and Observations tabs allow the user to filter their current view, using filters for either the variables or the observations. So, to visualize only the variables associated with a certain gene, the user would filter by Gene Symbol in the Variables tab. The user can filter variables by any column in the attached Annotation Table for the dataset. The Observations filter can be used, for example, to visualize only the observations associated with a certain treatment. The user can filter observations by any column in the attached Design Table for the dataset.

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Last update: 2009-04-27 20:53
Author: Matt Newman
Revision: 1.2

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