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Need help with Variables? Have a suggestion to make? Feel free to use the contact form to let us know!

General

What are the minimum requirements?

Variables runs on any iPad with iOS 5.0 or above.

Does Variables work with iCloud?

Not at the moment, but it is built entirely on Apple's technologies created for iCloud and will use the service as soon as it supports all the features Variables requires.

Where do the icons come from?

The app icon was kindly created by Sasha Godiaieva and some of the icons within the app come from the Glyphish package.

Modeling

What are the kinds of data understood by Variables?

The main broad data kinds that Variables can model and analyze are numerical and categorical. However the actual kind used inside the app is a bit more specific:

  • numerical variables can be continuous when they represent some measure of an object or count (discrete) when they represent counts of objects
  • categorical variables are divided into nominal when observations are grouped into classes with no inherent ordering (gender, country) and ordinal when such ordering is present (level of satisfaction)

You can always change the kind of a variable within the broad classes, but not between them.

Text and date/time variables are treated separately, see the question on context variables.

How does Variables handle text and dates?

Some variables cannot be directly used as part of the model and are utilized by Variables to provide context: 

  • label variables represent text that can be used to identify individual observations when you tap on them in a chart
  • time variables are used to provide temporal information for each observation and will be utilized much more in forthcoming releases

Why are some arrows missing?

Variables currenly does not support categorical variables with more than two categories as the target of a relationship. They can however be the source of a relationship and thus a predictor in a model.

Why is there no method X?

Some methods were omitted because we believe that they are inferior to the other ones already present in Variables (e.g. box plot versus a kernel density estimate). Others are definitely being considered, with the current focus being adding tools for categorical vs categorical relationships and incorporating date/time context variables in a meaningful way.

If you would like a method or a visualization to be added, please feel free to write us using the contact form.

Data

How can I transfer files from my computer to the iPad?

You can email the file and open the attachment in Variables (press and hold on the attachment in Mail to see the options) if the file is smaller than the the limits of your email account (typically ~10Mb). Alternatively, you can copy the file onto the iPad via iTunes in Apps -> File Sharing, or even put the file somewhere on the web and access it via Safari or a dedicated app like Dropbox.

Can I import data from Excel, Numbers or other programs?

Variables currently can only read comma-separated values (semicolons and tabs are fine as separators too) and will determine the kinds of data automatically. The good news is that most software that deals with data has the option to export CSV as it is the industry standard for data interchange.

Is there any upper limit on the size of a dataset?

There is no hard limit on neither the number of variables nor the number of observations. In practice, however, the size of the dataset impacts the drawing performance and the animations might stutter. On iPad 1 the dataset with less than 1 000 observations should have no issues whatsoever, and datasets as large as 100 000 can be analyzed depending on the properties of the dataset and the complexity of the model.

Is it possible to restore the sample dataset?

Yes, to do that you need to find Variables inside Settings.app on the main screen of your iPad and set the Restore flag in Sample dataset section to YES. The dataset named 'sample' will be replaced.