# n4Studies Plus vs SAPO

The clearest difference is review sentiment: SAPO at 100% against n4Studies Plus's 0%. SAPO also leads on price (Free vs $7.99) and update cadence (fortnightly vs every 2 months). n4Studies Plus's advantage is in-app purchases (none vs 2). On ads there is nothing between them.

SAPO is free to download; n4Studies Plus costs $7.99 up front. SAPO sells 2 in-app purchases, starting at $2.99 per month. n4Studies Plus asks for nothing beyond the download.

n4Studies Plus ships an update every 2 months, SAPO fortnightly. The most recent releases landed on September 15, 2026 and July 6, 2026 respectively.

## The numbers

| Metric | n4Studies Plus | SAPO |
| --- | --- | --- |
| Price | $7.99 | **Free** |
| Rating | **[3.0 (1 ratings)](https://appshunter.io/ios/app/n4studies-plus/id6450650727/reviews)** | — |
| Number of ratings | **1** | — |
| Positive reviews | 0.0% of reviews | **100.0% of reviews** |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 2 months | **Fortnightly** |
| Monetization | Paid | **Free with in-app purchases** |
| Size | 16 MB | 62 MB |
| Requires iOS | 16.0 | **13.0** |
| Devices | iPhone | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Chetta Ngamjarus](https://appshunter.io/developer/680516904) | [BIOMAXIMA INFORMACION Y EXPERIMENTACION CIENTIFICA SOCIEDAD LIMITADA](https://appshunter.io/developer/1794186533) |

## What reviewers say

### n4Studies Plus

[App page](https://appshunter.io/ios/app/n4studies-plus/id6450650727)

This app simplifies sample size and study power calculations for various research designs. It offers tools for regression, survival analysis, diagnostic studies, and more, helping users find calculations in minutes.

**Highlights:** Sample size calculation for regression, Sample size for survival analysis, Sample size for diagnostic and cross-over studies, Sample size for population means and proportions, Sample size for case-control and cohort studies, Study power calculations, Email output sharing

**Features:** macOS Compatibility

**In-app purchases:** none


### SAPO

[App page](https://appshunter.io/ios/app/sapo-ai-statistical-assistant/id6741438601)

This app offers advanced statistical analysis tools for researchers and students. It includes guided test selection, modeling, data visualization, and an AI assistant for interpretation. Generate publication-ready reports and calculate sample sizes.

**Highlights:** Statistical Test Guidance, Advanced Modeling Tools, Integrated AI Assistant, Database Manager, Sample Size Calculator, Automatic PDF Reports, Data Visualization

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Monthly subscription | $2.99 | per month |
| Yearly subscription | $22.99 | per year |


## Frequently asked questions

### Is n4Studies Plus free?

n4Studies Plus costs $7.99, with no in-app purchases.

### Is SAPO free?

SAPO is free to download, with in-app purchases available.

### Do n4Studies Plus or SAPO have ads?

Neither n4Studies Plus nor SAPO shows ads.

### Which is updated more often, n4Studies Plus or SAPO?

n4Studies Plus ships an update every 2 months, and SAPO fortnightly. Most recently, n4Studies Plus was updated on September 15, 2026 and SAPO on July 6, 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.*