sd.json

{
    "id": "sd",
    "summary": "Standard deviation",
    "description": "Computes the sample standard deviation, which quantifies the amount of variation of an array of numbers. It is defined to be the square root of the corresponding variance (see ``variance()``).\n\nA low standard deviation indicates that the values tend to be close to the expected value, while a high standard deviation indicates that the values are spread out over a wider range.\n\nAn array without non-`null` elements resolves always with `null`.",
    "categories": [
        "math > statistics",
        "reducer"
    ],
    "parameters": [
        {
            "name": "data",
            "description": "An array of numbers.",
            "schema": {
                "type": "array",
                "items": {
                    "type": [
                        "number",
                        "null"
                    ]
                }
            }
        },
        {
            "name": "ignore_nodata",
            "description": "Indicates whether no-data values are ignored or not. Ignores them by default. Setting this flag to `false` considers no-data values so that `null` is returned if any value is such a value.",
            "schema": {
                "type": "boolean"
            },
            "default": true,
            "optional": true
        }
    ],
    "returns": {
        "description": "The computed sample standard deviation.",
        "schema": {
            "type": [
                "number",
                "null"
            ]
        }
    },
    "examples": [
        {
            "arguments": {
                "data": [
                    -1,
                    1,
                    3,
                    null
                ]
            },
            "returns": 2
        },
        {
            "arguments": {
                "data": [
                    -1,
                    1,
                    3,
                    null
                ],
                "ignore_nodata": false
            },
            "returns": null
        },
        {
            "description": "The input array is empty: return `null`.",
            "arguments": {
                "data": []
            },
            "returns": null
        }
    ],
    "links": [
        {
            "rel": "about",
            "href": "http://mathworld.wolfram.com/StandardDeviation.html",
            "title": "Standard deviation explained by Wolfram MathWorld"
        }
    ],
    "process_graph": {
        "variance": {
            "process_id": "variance",
            "arguments": {
                "data": {
                    "from_parameter": "data"
                },
                "ignore_nodata": {
                    "from_parameter": "ignore_nodata"
                }
            }
        },
        "power": {
            "process_id": "power",
            "arguments": {
                "base": {
                    "from_node": "variance"
                },
                "p": 0.5
            },
            "result": true
        }
    }
}