Probability vs Z
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Probability
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.
- Compute probabilities
- Determine percentiles
- Plot probability density function
- Plot probability mass function
- Supports 10+ continuous distributions
- Supports 5+ discrete distributions
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Replace your statistical tables with an interactive, graphical app! Compute probabilities & percentiles, and plot the probability density/mass function for the normal (Gaussian), t, chi-square, F, exponential, gamma, beta, log-normal, and Uniform, binomial, geometric (2 versions), hypergeometric, Poisson, and negative binomial (2 versions) distributions. Now supports Español.
Z
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.
- Comprehensive Z-score tables
- Fast probability calculation
- User-friendly interface
- Educational tool for statistics
- Reference for data analysis
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Z-Table is a simple and powerful tool designed to help students, statisticians, and professionals look up Z-scores and corresponding probabilities with ease. Whether you're studying for an exam or working on data analysis, this app provides an efficient way to calculate and reference Z-scores. Key Features: Comprehensive Z-Score Tables: Access both positive and negative Z-tables to quickly look up critical Z-scores. Fast Probability Calculation: Find left-tail and right-tail probabilities with ease. User-Friendly Interface: The clean and minimal design ensures you can get the values you need without distractions. Educational Tool: Ideal for statistics students or professionals who frequently work with normal distributions. Why Choose Z-Table? Z-Table is optimized for speed and ease of use. Whether you are working on statistical analysis, preparing for exams, or just need a quick reference, Z-Table is the perfect companion. No ads, no distractions—just reliable and accurate statistical data at your fingertips. Who is this app for? Statistics students and teachers Data analysts and researchers Professionals in need of quick statistical references Download Z-Table today and simplify your statistical analysis process!
Screenshots
Verdict
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 device support (3 vs 1) and iOS requirement (12.0 vs 26.0). On rating, review sentiment, update cadence and in-app purchases there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
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 21, 2026 and October 9, 2026 respectively.
| Parameter | Probability | Z |
|---|---|---|
| Price | $1.99 — better | $2.99 |
| Rating | 4.9 (193 ratings) | 5.0 (1 ratings) — better |
| Positive reviews | 97.2% of reviews | 100.0% of reviews — better |
| Number of ratings | 193 — better | 1 |
| Update frequency | Every 3 months | Every 6 weeks — better |
| Ads | No — better | Yes |
| In-app purchases | No | No |
| Monetization | Free — better | Ad-supported |
| Devices | iPhone | iPhone, iPad, iPod — better |
| Requires iOS | 26.0 | 12.0 — better |
| Further details — not scored | ||
| Size | 7 MB | 32 MB |
| Age rating | 17+ | 4+ |
| Developer | Matthew Bognar | JanoGroup LLC |
Customer experience
Probability
Z
Bugs and requests
Probability
Requested features
7 requests- 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
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- Add options after graph rendering (area above, between, outside values)
- Consistent terms for df across distributions
Z
Not enough reviews yet to summarise bugs or requests.
In-app purchases
Probability
No in-app purchases
Z
No in-app purchases
Questions
Is Probability free?
Is Z free?
Which has better reviews, Probability or Z?
Do Probability or Z have ads?
Which is updated more often, Probability or Z?
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