# n4Studies Plus — n4Studies Plus

> Calculates sample size and study power for diverse research designs. (iPhone/iPad app by Chetta Ngamjarus.)

- Source: https://appshunter.io/ios/app/n4studies-plus/id6450650727 (this page in markdown: same URL + `.md`)
- Developer: [Chetta Ngamjarus](https://appshunter.io/developer/680516904)
- Category: Education, Productivity
- Price: $7.99
- Rating: 3.00/5 from 1 App Store ratings · 1 written reviews indexed
- Age rating: 4+
- Requires: iOS 16.0 · 16 MB
- Languages: American English
- Released: 2023-06-26
- Data updated: 2026-09-02
- Monetization: paid
- User reviews in markdown: https://appshunter.io/ios/app/n4studies-plus/id6450650727/reviews.md

## What is n4Studies Plus?

Ease to calculate the sample size with n4Studies Plus.

n4Studies Plus makes it easy to calculate the sample size and the power of a study in various study designs. It comes with ABSOLUTELY NO WARRANTY. However, It can be helped to learn and find the ways to calculate the sample size and power of the study in minutes.

Key features:
• Calculate the sample size for simple and multiple linear regression, logistic regression
• Calculate the sample size for survival analysis e.g. compare 2 survival curves, compare for equality between 2 hazard rates etc.
• Calculate the sample size for diagnostic study, cross-over study
• Calculate the sample size for estimating an infinite population mean, finite population mean, infinite population proportion and finite population proportion
• Calculate the sample size for comparing two population means and two population proportions
• Calculate the sample size for the Case-Control for study, Matched Case-Control study, Cohort study, Randomized Controlled Trial, Non-inferiority trial and Equivalence trial
• Calculate the power of a study for comparing two population means and two population proportions
• Calculate the power of a study for the Case-Control for study, Matched Case-Control study, Cohort study, Randomized Controlled Trial, Non-inferiority trial and Equivalence trial
• Sample size and power calculations for measures of Agreement (both Kappa statistic and Intraclass correlation coefficients)
• You can send a output via Email to your colleagues

## Key features

- 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

## Recent user reviews (1 of 1)

All indexed reviews: https://appshunter.io/ios/app/n4studies-plus/id6450650727/reviews.md

### 3/5 — Need to Add More One-Sided Test Functions and α = 0.025 Support

*2026-05-22*

Although support for one-sided hypothesis testing has been added for some statistical methods, the one-sided calculation for non-inferiority tests comparing two proportions still appears to be missing or incomplete. This is a very important feature for clinical trial design and should be supported explicitly.

In addition, I strongly recommend adding an option for α = 0.025, alongside the currently available α values of 0.01, 0.05, and 0.1. A one-sided α = 0.025 is widely used in confirmatory clinical trials, especially in superiority and non-inferiority study designs following regulatory guidance and common industry practice.

## Frequently asked questions about n4Studies Plus

### What is n4Studies Plus used for?

n4Studies Plus is designed to help users easily calculate the sample size and statistical power for a wide range of study designs. It covers various statistical methods like regression, survival analysis, and diagnostic studies, aiming to simplify these complex calculations.

### What types of study designs does n4Studies Plus support for sample size calculation?

n4Studies Plus supports sample size calculations for simple and multiple linear regression, logistic regression, survival analysis (comparing curves, hazard rates), diagnostic studies, cross-over studies, infinite/finite population means and proportions, comparing two population means and proportions, case-control studies (matched and unmatched), cohort studies, randomized controlled trials, non-inferiority trials, and equivalence trials.

### Can n4Studies Plus calculate study power?

Yes, n4Studies Plus can calculate the statistical power of a study. This includes power calculations for comparing two population means and two population proportions, as well as for case-control studies, matched case-control studies, cohort studies, randomized controlled trials, non-inferiority trials, and equivalence trials.

### What is the price of n4Studies Plus?

n4Studies Plus is a paid application priced at $7.99. This one-time purchase grants access to all its features for calculating sample size and study power.

### On which devices can I use n4Studies Plus?

Currently, n4Studies Plus is supported on iPhones. The app is designed to run on iOS devices, providing its statistical calculation tools for users on the go.

### How often is n4Studies Plus updated?

The latest version of n4Studies Plus is 1.4, and it was last updated on February 16, 2024. This indicates regular maintenance and potential feature additions by the developer.

### Does n4Studies Plus have ads?

No, n4Studies Plus does not contain advertisements. As a paid application, it offers an ad-free experience, allowing users to focus on their calculations without interruption.

### What is the user sentiment for n4Studies Plus based on ratings?

Based on the available data, n4Studies Plus has a rating of 3.0 stars from 1 rating. This suggests a mixed or limited user reception, and more reviews would be needed for a comprehensive understanding of user sentiment.

## Version history (last 5 releases)

### 1.4 — 2024-02-16

Sample size calculations for one-tailed test of one population, two populations and correlation coefficient analysis were added in this version 1.4

### 1.3 — 2023-12-21

Version 1.3: Sample size and power calculations for measures of Agreement (both Kappa statistic and Intraclass correlation coefficients) were added in this version.

### 1.2 — 2023-08-04

Version 1.2: Add the probability calculations from odds ratio (OR.) and relative risk (RR.)

### 1.1 — 2023-06-30

- Fix issues for images attachments

### 1.0 — 2023-06-27

No release notes.

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## More apps by Chetta Ngamjarus

- [n4Studies](https://appshunter.io/ios/app/n4studies/id680516901)

All apps by Chetta Ngamjarus: https://appshunter.io/developer/680516904

## Related topics

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-09-02.*