Standard Deviation
Terms of use
Last updated: 9 September 2026. These terms cover the Android app Standard Deviation Calculator (package tq.tech.standarddeviation), provided by TQ Tech. By using the app you agree to these terms. If you do not agree, do not use the paid Lifetime Pro product.
What the app is
The app is a statistics calculator. Results are for informational use. You are responsible for how you apply them. We do not guarantee uninterrupted service, ad availability, or that every device will complete a purchase if Google Play is unavailable.
License
We grant you a personal, non-exclusive license to use the app on Android devices you own or control, subject to Google Play’s terms.
Lifetime Pro
Lifetime Pro is an optional unlock. It removes ads, keeps 8 decimal places on every result without watching a video, and unlocks PDF export of the working. Image export, sample and population standard deviation, and history remain available without a purchase.
Price and billing
Lifetime Pro is a one-time purchase. It is not a subscription, does not auto-renew, and is not billed again unless you buy it on another Google account. The price shown in the app is the Google Play price for your account and country. Payment is processed only by Google Play Billing. In-app prices match the Play billing sheet. The USD list price used in the app copy is $4.99; Play localizes this.
Restore
If you already bought Lifetime Pro with the Google account signed into this device, use Restore purchases on the paywall or in Settings. Restore does not charge you again.
Refunds
Refunds are handled by Google Play under Google’s refund policy. We cannot process card refunds inside the app.
Acceptable use
Do not misuse the app, attempt to interfere with billing, or use it in a way that violates law.
Changes
We may update these terms when the product changes. The updated date appears at the top of this page. Continued use after an update means you accept the revised terms.