# Probability vs Z

The clearest difference is ads: Probability at none against Z's shown. Probability also leads on ratings volume (193 vs 1) and price ($1.99 vs $2.99). Z's advantage is iOS requirement (12.0 vs 14.0). On rating, review sentiment, update cadence and in-app purchases there is nothing between them.

Probability costs $1.99 and Z $2.99 up front. Neither carries in-app purchases, so what you see is what you pay.

On the App Store both sit at effectively the same score — 4.9 for Probability against 5.0 for Z. That said, the two scores are not equally well evidenced: Probability has 193 ratings behind it against 1, so its average is the more settled of the two. Written reviews are what separate them: 97% of Probability's written reviews are positive against 100% of Z's.

Probability ships an update every 3 months, Z every 6 weeks. The most recent releases landed on October 2, 2026 and September 22, 2026 respectively.

## The numbers

| Metric | Probability | Z |
| --- | --- | --- |
| Price | **$1.99** | $2.99 |
| Rating | [4.9 (193 ratings)](https://appshunter.io/ios/app/probability-distributions/id889106396/reviews) | **[5.0 (1 ratings)](https://appshunter.io/ios/app/z-table-statistics/id6738610691/reviews)** |
| Number of ratings | **193** | 1 |
| Positive reviews | 97.2% of reviews | **100.0% of reviews** |
| In-app purchases | No | No |
| Ads | **No** | Yes |
| Update frequency | Every 3 months | **Every 6 weeks** |
| Monetization | **Free** | Ad-supported |
| Size | 2 MB | 32 MB |
| Requires iOS | 14.0 | **12.0** |
| Devices | iPhone, iPod | **iPhone, iPad, iPod** |
| Age rating | 17+ | 4+ |
| Developer | [Matthew Bognar](https://appshunter.io/developer/889106399) | [JanoGroup LLC](https://appshunter.io/developer/1781461557) |

## What reviewers say

### Probability

[App page](https://appshunter.io/ios/app/probability-distributions/id889106396)

Calculate probabilities, find percentiles, and visualize probability density or mass functions for a wide range of continuous and discrete statistical distributions. Explore common distributions like normal, binomial, Poisson, and many more.

**Highlights:** Compute probabilities, Determine percentiles, Plot probability density function, Plot probability mass function, Supports 10+ continuous distributions, Supports 5+ discrete distributions

**Features:** Vision Pro support

**In-app purchases:** none

**What reviewers like**

- 👍 Easy to use interface
- 📊 Great for probability distributions
- 💡 Useful for checking work and homework
- 💰 Free advanced functions
- 📈 Visualizes data and distributions

**What reviewers complain about**

- 🚫 Not allowed on some exams
- 🤔 Some users want more features

**Requested features**

- Exam mode similar to Geogebra
- Poisson distribution
- Allow setting plot boundaries (e.g., for Beta distribution)
- Make formulae available in offline mode
- Clearly introduce parameters


### Z

[App page](https://appshunter.io/ios/app/z-table-statistics/id6738610691)

This app provides a quick and easy way for students and professionals to look up Z-scores and calculate corresponding probabilities. It features comprehensive Z-score tables and a user-friendly interface for efficient statistical analysis.

**Highlights:** Comprehensive Z-score tables, Fast probability calculation, User-friendly interface, Educational tool for statistics, Reference for data analysis

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Probability free?

Probability costs $1.99, with no in-app purchases.

### Is Z free?

Z costs $2.99, with no in-app purchases.

### Which has better reviews, Probability or Z?

Z is rated higher. Probability averages 4.9 out of 5 from 193 ratings, while Z averages 5.0 from 1 ratings.

### Do Probability or Z have ads?

Z shows ads; Probability does not.

### Which is updated more often, Probability or Z?

Probability ships an update every 3 months, and Z every 6 weeks. Most recently, Probability was updated on October 2, 2026 and Z on September 22, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*