Glossary
Glossary |
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Glossary
attribute A descriptor of a case, for example, the height of a person is an attribute.
bar chart A plot of a categorical attribute in which each category has a bar whose height is determined by a formula, count( ) by default.
bin For a numeric attribute, a range of values. The number of cases whose attribute values lie within this range is used to determine the height of a bar in a histogram.
bin alignment The value on one end or the other of a bin. For a histogram, setting the bin alignment at 1.5 guarantees that the lower bound of one bin will be 1.5.
bin width The upper value minus the lower value of a bin.
bivariate Involving two attributes. For example, a scatter plot is a bivariate plot because it uses an attribute on each of its two axes.
Boolean Having a value of either true or false.
caption The word or phrase that appears under a case icon in an open (expanded) collection. Also appears in the status bar when the mouse pointer is over a that case’s point in a graph.
caret The blinking indicator that shows where the next typed character will appear.
case An individual record in a collection, for example, a person who filled out a survey, or a set of measurements taken at a given time.
case icon The look of a case in an open (expanded) collection. By default a gold, green, or blue ball, but controllable by formula.
categorical Having values drawn from a set of possibilities (categories). The race of a person and the color of a bead are categorical attributes.
category One of a set of possible values of an attribute, for example, “These paintings all have the category Gothic as their value for Style.”
category set The possible values for a categorical attribute. For example, the category set Gender consists of the values male and female.
collect measures To record a collection’s measures as values of a case in a measures collection. Typically, this is done repeatedly to build up a distribution for each collected measure.
collection The container for data in Fathom.
comments A textual description of a collection. Can be viewed in a collection’s inspector.
cursor Depending on context, either the position of the mouse pointer on the screen or the position of the caret within text.
data Generic term for the finest grain of information. Fathom is software for working with data.
distribution The arrangement of values for an attribute with respect to their frequency. For example, the distribution of heights for this collection of students peaks at about 170 cm.
document Generic term for a Fathom file. A Fathom document typically contains one or more collections, graphs, tables, sliders, and text objects.
dot plot A graph of a numeric attribute in which each case appears as a dot. In a stacked dot plot, the dots pile on top of each other to show the shape of the attribute’s distribution.
drag A common operation in Fathom, namely, to click, hold, and move the mouse on some object to change its state or to link it to some other object.
export In Fathom, to create a text file of the data contained in a collection.
Fathom 1) To measure the depth of water. 2) To understand deeply. 3) A unit of linear measure equal to 6 feet. 4) The name of a piece of dynamic data analysis software.
file The unit of information storage in a modern computer operating system. Fathom documents when saved to disk are files.
filter In Fathom, to prevent certain cases from being displayed or used in an analysis. Any Fathom object that displays or analyzes data can have a filter. A filter on a collection affects all objects that use that collection’s data.
formula In Fathom a symbolic expression consisting of attributes, functions, operators, and constants that can be evaluated. For example, an attribute may have its values determined by a formula.
function In Fathom a formula with one variable that takes values from a graph axis in order to show a line plot of that function.
histogram A plot of the values of a continuous attribute in which the heights of bars are proportional to the density of cases whose values fall within the range of values corresponding to each bar. Fathom’s histograms have bars of uniform width. (Compare with ntigram.)
household One of the possible units of analysis for census microdata. Household attributes pertain to the structure in which people live or a group of people as a whole.
hypothesis A proposed explanation of the observed data.
image In Fathom, the picture used as a case icon in an open (expanded) collection. By default a gold, green, or blue ball, but can be determined formulaically or pasted onto individual cases.
import In Fathom, to bring data into Fathom from some source that is not a Fathom document, for example, from a text file, Web page, or census microdata server.
inference A conclusion based on evidence. In Fathom, the following objects are used for statistical inference: interval estimates, hypothesis tests, and linear models.
inspector In Fathom, a floating window that displays information about an object embedded in the document.
inspector pane In Fathom, a portion of an inspector panel, for example, the left pane of the Microdata panel allows choice of subsets of attributes to import.
inspector panel In Fathom, one of several choices of displays of information in an inspector. A basic collection inspector has panels for cases, measures, comments, display attributes, and categories.
interval estimate A proposed range of reasonable values for a population parameter based on sample data. Assumes a confidence level and typically specified as a central value plus or minus a range.
IPUMS Integrated Public-Use Microdata Series. In Fathom, refers to the project at the University of Minnesota Center for Population Studies from which Fathom obtains U.S. census microdata.
join In Fathom, the process of merging two collections by using an attribute in one collection as a “key” to cases in another (also, “table join”).
least-squares Refers to a process of fitting a function to data in which the sum of squares of residuals is minimized.
legend The portion of a graph that shows the key for symbols or colors used in a plot.
link axes In Fathom, to specify that two or more numeric axis scales will have the same scales so that a change in one will cause a change in all.
measure In Fathom, refers to a quantity, typically computed by a formula, that applies to an entire collection. Measures are specified in the Measures panel of a collection’s inspector.
microdata Data about individuals, as opposed to summary data. (Each person’s sex and income in a collection of people is raw data or microdata; proportions of females and median incomes in a collection of provinces is summary data.) Fathom was designed to work with microdata but does less well with summary data.
model A theoretical construct used to explain observations and predict new observations. There are many ways to construct models in Fathom.
multiple regression The fitting of data using more than one attribute to fit the observed values of a response attribute. Fathom’s model object can compute a multiple linear regression, the product of which is a linear equation for the response in terms of one or more predictor attributes.
multivariate Involving multiple attributes. For example, a scatter plot with a legend attribute is a multivariate graph because it involves three attributes.
nominal Categorical, having named values.
ntigram A graphical representation of the values of an attribute in which each of several bars arranged along a numeric axis has equal area and that area is proportional to the count of cases whose values for the attribute lie within the range of the bin corresponding to each bar.
numeric Having a value that is a number (sometimes called “continuous”). In contrast to categorical attributes.
object In Fathom, selectable entities within a Fathom document. A graph and a case table are objects, but an inspector window is not because it floats above the document rather than living within it.
operator In a Fathom, formula a symbol that indicates something to be done to one or more values. For example, the division operator divides one value by another and returns the result.
parameter A value that determines which of a family of functions or models is under consideration at the moment. In Fathom, sliders are used as parameters.
percentile Given a value for an attribute, the percent of values for that attribute that are less than or equal to the given value.
plotted function In Fathom, a line or curve on a plot determined by a formula using one axis as its domain for a dummy variable in the formula.
plotted value A line on a plot perpendicular to an axis, where the position of the line along the axis is determined by a formula.
properties In Fathom properties are attributes of objects other than collections. Graphs and sliders have properties whose values determine their appearance and behavior.
quantity A number with a unit. Attribute values in Fathom can be either plain numbers or quantities.
raw data The data as it was originally gathered, as opposed to summary data.
recode To take the values of one attribute and use them to determine (usually formulaically) the values of another attribute. Recoding numeric choices to their corresponding textual meaning can greatly increase one’s ability to understand data.
redo In computer software, refers to the act of making something that was undone happen again.
residual The observed value minus the predicted value.
revert collection In Fathom, to return the values of a collection’s attributes to their last saved values without changing other objects in a document.
ribbon chart A plot in which a rectangle representing all the cases is divided into sub-portions using one or two categorical attributes, such that the area of each sub-portion is proportional to the count of cases having certain values of the categorical attributes.
sample To draw cases from a population. In Fathom, sampling is nearly always random.
scatter plot A graphical representation in which numeric attributes placed on each axis determine the coordinates of points representing cases in the collection.
scramble In Fathom, to take one attribute in a collection and reassign its values randomly to that attribute. Scrambling is typically used to simulate a situation in which two attributes are independent of each other.
shelf In Fathom, the place at the top of the application (Win) or document (Mac) window that contains iconic representations of the objects that can be placed in the document.
simulation To represent some process (for example, rolling a die) through some other means, usually for the purpose of discovering properties of that process. Fathom provides many tools for constructing simulations.
slider In Fathom, an object representing a named number or quantity such that the name can be used in formulas to represent the slider’s value. The slider’s value can be determined by the position of its “thumb,” by typing a new value, or by formula.
stack attributes In Fathom, the process of reorganizing the data so that there are two attributes, named “group” and “value” by default, where the values of the group attribute are the names of the attributes. The process can be visualized as taking each attribute of the collection and stacking it under its predecessor.
statistic A quantity computed from data.
status bar A pane found at the bottom of an application (Windows) or document (Mac) window that displays some information relevant to the current mouse position.
string Textual information. An attribute treated as categorical typically has string values rather than numeric values.
summary data Data that summarizes raw data. Summary data typically consists of many fewer values than its raw data, and contains less “information” than the raw data. Proportions and means are summary data; values about individuals are raw data, from which summary statistics are computed.
table join The operation of merging two collections by dragging an attribute from one collection onto an attribute name appearing in a case table. The result is that information from the first collection is brought into the second using the attribute dropped upon as a key to the dragged attribute.
test In Fathom, “test” typically refers to a hypothesis test object used to determine whether certain observations can be explained by chance or not.
test statistic A computed quantity whose distribution, when the null hypothesis is true, is known or can be determined. For a given inference, the test statistic is used to determine how likely it is that the data can be explained by the null hypothesis.
undo In software applications, to reverse the most recent action. Fathom’s undo capabilities allow you to step a document back to the state at which it was last opened (or created).
unit The standard of measurement in a physical dimension to be considered as 1; for example, an attribute value of 3.4 Joules has Joules as its unit.
univariate Pertaining to something determined by one variable or attribute. In Fathom a dot plot with a single attribute is a univariate plot. The mean and median are univariate measures.
URL Uniform Resource Locator. The address of a given Web page. Fathom’s Import From URL command takes a URL and attempts to convert the indicated page into a collection of data.
value The number, quantity, or string corresponding to a given attribute for each case. An attribute need not have a value for a given case, in which situation the value is said not to exist.
window In Fathom, documents and inspectors appear in windows. An object in a document, such as a graph, however, is not a separate window because it is constrained to stay within the document window.
zoom To expand or contract a numeric scale on a graph. To “zoom in” is to expand the scale so that points appear farther apart. |