Its apps like this where I wonder if they only exist to record statistics for a study. Sure the program does something but the interesting numbers are on why it was downloaded, when/where it was used and for how long. Personally I would love to read the submitted bug reports from users complaining about found flaws or perceived inaccuracies.
I would not take this seriously except that the app includes "digit ratio" (index and ring finger), as a factor. Digit ratio is coincidentally what I used to make some assumptions about Rosa in one of her earlier posts (Intel nail polish, I believe).
Of course it's for Android but not the reason you think. App developers have been choosing Android at a greater rate than iOS. This is part of the reason the Google Play store has surpassed the App Store for number of apps.