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March 31, 2011 • Reviews

iPad App Review: Biostatistics

Since my day job is as a statistician, when I saw that an app called Biostatistics had been released on the iTunes App Store, I simply had to check it out. Developer Stephen S. Ashley was kind enough to provide me with a review code for the full version. There are two things I wanted to highlight: the statistics, and the interface.

The Hype:
The Biostatistics app™ provides descriptive statistics and statistical tests and procedures of interest primarily to students and researchers in the life sciences. The provided tests and procedures may also prove useful to those in other fields who draw inferences about large populations from measurements taken from random samples. The Biostatistics app runs on the Apple® iPad™ and is available for purchase in the Apple App StoreSM.

The Reality:

As mentioned, there are two main things to deal with for a statistics app: how you get the data into and out of the app, and how well it is handled by the app itself. I was able to test the app against standard tools such as Minitab, JMP and R for a suite of data sets, but due to the proprietary nature of the data itself I can’t share any of the specifics of that here. So all of my analytic statements will be rather vague and sweeping.

When you start Biostatistics you get an array of large descriptive buttons showing all of the functionality available. You have rows based on the type of data (continuous, nominal, ordinal or survival time), and columns by how you will look across your data set. In all there are 17 functions available that span a broad spectrum of useful analyses from a simple t-Test to a more interesting Spearman Rank Correlation test.

Tapping on one of these buttons will bring you to an empty data sheet. From here you can simply enter data into the worksheet and go ahead with the computation. However, it is often more useful to bring in data collected elsewhere. Fortunately, Biostatistics allows you to copy & paste from other apps, which means that if you have shared a spreadsheet using Numbers, you can simply open it up, copy the area of interest, and paste it into your Biostatistics worksheet.

From the data sheet, simply tap ‘Compute’ and a results sheet will appear with all of the relevant numerical information. There are no graphs, just a simple and clear output sheet showing you the results. When you are done, your data sheet is stored using a time stamp, but you can rename it however you like.

The one thing I need to mention is that Biostatistics is not like Excel – it isn’t a spreadsheet program with analysis tools tacked on. Quite the opposite, in fact – getting data into the spreadsheets is the biggest pain! If you don’t paste in external data, you will be entering it in one cell at a time through a little pop-up. It really seems there should be a simpler way, maybe a virtual numeric keypad on-screen at all times … but since Apple’s Numbers does the same thing I guess it is a standard practice. Suffice to say that if you are entering more than a couple dozen values you’ll want to do it elsewhere.

Statistical Functionality:
The bottom line with a statistics program is whether or not it provides correct answers. I am old enough to have seen the transitions of statistical tools from mainframes to desktop Unix workstations to desktop PC’s and more recently to menu driven graphical interface software systems. With each new iteration there are always issues brought up around accuracy of calculations.

I was able to check all of the continuous data tests – t-tests, ANOVA, regressions, as well as Chi Square and other tests on nominal data. In every case I found the results to be accurate and precise and well matched to what I got on my normal arsenal of analysis tools (JMP, Minitab, R).

This isn’t a graphical analysis program such as JMP, it is a numerical analysis product meant to provide simple and direct answers to statistical questions. In that regard it works very well – you get everything you need to know presented simply and clearly.

Problems and Patches:
The 1.002 release added the ability to copy and paste between applications … but not all applications. Documents to Go, for example, would open my Google Docs spreadsheets and I could copy data … but Biostatistics wouldn’t paste it. Working with Apple’s Numbers is no issue, as I could easily copy and paste sections of spreadsheets. Since I prefer Documents to Go for the Excel-like interface, I hope that Biostatistics adds those capabilities in the future.

Another issue I had was with stability. After updating my iPad to iOS 4.3, Biostatistics would crash on me immediately after launch. I uninstalled and reinstalled and it seemed to work fine. However, I noticed that after some use it would become less stable and start crashing fairly regularly. I spoke with the developer and they hadn’t been updated on their iPad yet but had heard similar issues from other developers based on an Apple API change in the latest iOS release. Hopefully the next patch will clear this up!

The program is called Biostatistics, but that is perhaps not accurate. Certainly things like Spearman test are focused on life sciences, but in general the tools available here are broadly applicable for anyone doing data analysis.

The iPad has been a great enabling tool because it is thin and light and has long battery life, and an app like Biostatistics is a perfect fit: it allows you to bring your iPad into just about any situation, enter and quickly analyze data on the go.

At $25, Biostatistics is a fairly expensive app – but the value is something that you will immediately either see or not see. If you are like me and work in various settings and constantly dealing with data, an app like this looks like a great bargain compared to carrying a laptop and using software that costs thousands of dollars for a simple t-Test. My advice? Check out the Student Edition and see how this will meet your needs. And let’s hope that great business tools like these keep coming to the app store!

Review: Biostatistics

Where to Buy: iTunes App Store

Price: $24.99

What I Like: Accurate statistics; easy to enter data or paste from Numbers; great simple output

What Needs Improvement: Crashing with iOS 4.3; limited pasting ability

Source: Review code provided by developer

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