The purpose of data tables is to present tabular information in a grid, or matrix, and to have column or rows that show the meaning of the information in the grid. Sighted users can visually scan a table. They can quickly make visual associations between data in the table and their appropriate row and/or column headers. Someone that cannot see the table cannot make these visual associations, so proper markup must be used to make a programmatic association between elements within the table. When the proper HTML markup is in place, users of screen readers can navigate through data tables one cell at a time, and they will hear the column and row headers spoken to them. Show
Table CaptionsData tables very often have brief descriptive text before or after the table that indicates the content of that table. This text should be associated to its respective table using the <table> While it is not necessary for each table to have a caption, a caption is generally very helpful. If present, it should be associated to the table using the Identify Row and Column HeadersA critical step toward creating an accessible data table is to designate row and/or column headers. In the markup, the Table headers should never be empty. This is particularly of concern for the top-left cell of some tables Associate the Data Cells with the Appropriate HeadersNow that we've created headers, we need to associate the data cells with the appropriate headers. The scope attributeThe scope attribute identifies whether a table header is a column header or a row header. Here is the markup for the table, using the <table> The All Spanned headersScope will apply even if the table is complex with multiple levels of headers (such as in spanned cells). The scope of a table header will apply to all cells over which that header spans. Shelly's DaughtersNameAgeBirthdayby birthJackie5April 5Beth8January 14by marriageBeth8January 14In this example, the "by birth" row header has a scope of row, as do the headers with the names. The cell showing the age for Jackie will have 3 headers - one column header ("Age") and two row headers ("by birth" and "Jackie"). A screen reader would identify all of them, including the data cell content (e.g., it might read "by birth. Jackie. Age. 5."). Note Despite being standard markup for tables for many years, some screen readers still do not fully support complex tables with spanned or multiple levels of row and/or column headers. When possible, try to 'flatten' the table and avoid spanned cells and multiple levels of header cells. The <caption>4 and <caption>5 attributesAnother way to associate data cells and headers is to use the In extremely complex tables where With this approach, each Again, it should be emphasized that this method is more complex, uses much more markup (and potential to become broken), and is rarely necessary (use scope instead). Use Proportional Sizing, Rather than Absolute SizingThe rule that applies to layout tables also applies to data tables. Let the browser window determine the width of the table whenever possible, to reduce the horizontal scrolling required of those with low vision. If cell widths need to be defined, use relative values, such a percentages, rather than pixel values. Defined cell heights should generally be avoided so the cell can expand downward to accommodate its content - something especially useful for users with low vision that may enlarge text content. Other table markupSummaryThe thead, tfoot, and tbodyThe Is a scale of measurement which are data that are consider as labels or names used to identify attributes of the element?A nominal variable is a type of variable that is used to name, label or categorize particular attributes that are being measured. It takes qualitative values representing different categories, and there is no intrinsic ordering of these categories.
What is an attribute whose value is indicated by a label?Data a set of observations (a set of possible outcomes); most data can be put into two groups: qualitative (an attribute whose value is indicated by a label) or quantitative (an attribute whose value is indicated by a number).
What are labels used for in data sets quizlet?a Label is a special variable used in some data sets to distinguish the different cases. a Variable is a characteristic of a case.
When the data have the properties of interval data and the ratio of two values is meaningful the variable has which scale of measurement nominal ordinal interval ratio?An interval scale is one where there is order and the difference between two values is meaningful. Examples of interval variables include: temperature (Farenheit), temperature (Celcius), pH, SAT score (200-800), credit score (300-850).
|