Comparison

Probability vs Z

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

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.

Highlights
  • Compute probabilities
  • Determine percentiles
  • Plot probability density function
  • Plot probability mass function
  • Supports 10+ continuous distributions
  • Supports 5+ discrete distributions
Features
Currently charting
Read full description

Compute probabilities, determine percentiles, and plot the probability density function for the normal (Gaussian), t, chi-square, F, exponential, gamma, beta, log-normal, Pareto, and Weibull distributions. Compute probabilities, approximate percentiles, and plot the probability mass function for the binomial, geometric, hypergeometric, Poisson, and negative binomial distributions.

About

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.

Highlights
  • Comprehensive Z-score tables
  • Fast probability calculation
  • User-friendly interface
  • Educational tool for statistics
  • Reference for data analysis
Features
Read full description

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

Probability3 screens
Z4 screens

Verdict

The call

The clearest difference is ads: Probability at none against Z's shown. Probability also leads on ratings volume (193 vs 1) and chart position (#144 vs unranked). 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.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

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

ReceptionRating · Positive reviews · Number of ratings

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.

UpkeepUpdate frequency

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.

Scorecard6 real differences · 5 level
Probability versus Z: the parameters behind the verdict, then further details
ParameterProbabilityZ
Price$1.99 — better$2.99
Rating4.9 (193 ratings)5.0 (1 ratings) — better
Positive reviews97.2% of reviews100.0% of reviews — better
Number of ratings193 — better1
Update frequencyEvery 3 monthsEvery 6 weeks — better
AdsNo — betterYes
In-app purchasesNoNo
MonetizationFree — betterAd-supported
Best chart rank#144 — better—
DevicesiPhone, iPodiPhone, iPad, iPod — better
Requires iOS14.012.0 — better
Further details — not scored
Size2 MB32 MB
Age rating17+4+
DeveloperMatthew BognarJanoGroup LLC

Customer experience

Probability

All ratings193 ratings
Positive96.9%
Neutral1.0%
Negative2.1%
Written reviews71 reviews
Positive97.2%
Neutral1.4%
Negative1.4%

Z

All ratings1 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews1 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

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
Show 2 more
  • 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

None

Probability

No in-app purchases

None

Z

No in-app purchases

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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