# t-Test Calculator API

> For the complete documentation index, see [llms.txt](/llms.txt).

Run one-sample, paired, or independent two-sample t-tests with Welch or pooled variance, p-value, critical value, confidence interval, and Cohen's d.

Use this endpoint to add the tool to your app, site, workflow, or agent without rebuilding formulas, validation, examples, and docs.

- Slug: `t-test-calculator`
- Category: `math`
- Version: `2026-04-22`
- Credits per successful call: 1
- Starts on: free
- Max payload: 262144 bytes
- Privacy mode: `hash_only`
- Available on: free, starter, pro, business, scale
- Browser tool: https://miniwebtool.com/t-test-calculator/

## Endpoint

`POST https://api.miniwebtool.com/v1/tools/t-test-calculator/run`

## Request body

| Field | Type | Required | Description |
| --- | --- | --- | --- |
| `test_type` | `str` | no | two_sample | paired | one_sample Choices: two_sample, paired, one_sample |
| `group1` | `str` | no | first sample values separated by comma, space, or newline |
| `group2` | `str` | no | second sample values (two_sample and paired tests) |
| `mu` | `float` | no | hypothesised mean (one_sample) or hypothesised mean difference |
| `equal_variance` | `str` | no | no | yes Choices: no, yes |
| `tail` | `str` | no | two | left | right Choices: two, left, right |
| `alpha` | `str` | no | 0.05 | 0.01 | 0.10 Choices: 0.05, 0.01, 0.10 |
| `precision` | `int` | no | decimal places, 2-10 |

## Example request

```json
{
  "test_type": "two_sample",
  "group1": "23, 25, 28, 22, 27, 26, 24, 29",
  "group2": "31, 29, 35, 33, 30, 34, 32, 36",
  "tail": "two",
  "alpha": "0.05"
}
```

## cURL

```bash
curl -X POST https://api.miniwebtool.com/v1/tools/t-test-calculator/run \
  -H 'Authorization: Bearer mwt_live_YOUR_KEY' \
  -H 'Content-Type: application/json' \
  -d '{"test_type":"two_sample","group1":"23, 25, 28, 22, 27, 26, 24, 29","group2":"31, 29, 35, 33, 30, 34, 32, 36","tail":"two","alpha":"0.05"}'
```

## Response envelope

```json
{
  "request_id": "01K...",
  "tool": "t-test-calculator",
  "tool_version": "2026-04-22",
  "credits_used": 1,
  "result": {}
}
```

## Errors

Errors are RFC 7807 `application/problem+json`. Branch on `code`, not `title`.

## MCP

Agents can discover and call this tool through `https://api.miniwebtool.com/mcp` or `https://api.miniwebtool.com/v1/mcp` using MCP `tools/list` and `tools/call`.

## Frequently asked

### What does the t-Test Calculator API do?

Run one-sample, paired, or independent two-sample t-tests with Welch or pooled variance, p-value, critical value, confidence interval, and Cohen's d. Use it to add this utility without rebuilding formulas, validation, examples, and documentation.

### How much does one call cost?

1 credit per successful call. Failed calls do not bill.

### What parameters are required?

Required fields: (none). Full schema at `https://api.miniwebtool.com/v1/openapi.json`.

### Is this deterministic?

Yes. Same input, same output. Tool version: 2026-04-22.