GraphPad Prism 8 User Guide

Entering dates or elapsed times as X

Entering dates or elapsed times as X

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Entering dates or elapsed times as X

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Formatting the table to enter dates or times as X values

From the Welcome or New Table dialogs, you can choose to format the X column for entry of dates or elapsed time instead of X values.


If you forgot to format the table when you created it, use Change..Format data table to format the X values for dates or times.


Entering times or dates

If you choose elapsed time, enter time as hh:mm or hh:mm:ss. For example, enter 1:12:30.2 to enter an elapsed time of 1 hour, 12 minutes, 30.2 seconds.

If you chose to enter dates, you can enter dates in almost any format. Prism will figure out what you meant and display the date on the table in a standard format (that you cannot change). The only ambiguity is if you enter a date like 1/2/2014 or 1-2-2014. Is that January 2 or February 1? The convention depends on where in the world you live. Make your choice on the bottom of the View tab of the Preference dialog.

date preference

If you enter a year with two digits, Prism Windows follows the choices made in the Date tab of the Additional Settings dialog, accessed from the Format Tab of the Regional settings control panel.

When Prism shows a ? in the data table

If Prism doesn't understand the date or time you entered, it will show ? in the data table. This is treated as a missing or blank value for graphing and analyses. When you click on the cell to edit, Prism will show you exactly what you entered for editing.

Converting dates or times to values for analyses

When you analyze these data and make some kinds of graph, Prism converts the dates or elapsed times to values. Choose the units and (for dates) starting date on the Format Data Table dialog. Note that the choice of months is not offered, because months have different lengths. Years also have different lengths, so if you choose years, Prism does the conversion based on 365.25 days per year.

date time conversion

Formatting dates and times on the graph

The Format Axes dialog will present several choices for numbering format.