normality_test_fl()

The function normality_test_fl() is a UDF (user-defined function) that performs the Normality Test.

Syntax

T | invoke normality_test_fl(data, test_statistic,p_value)

Parameters

Function definition

You can define the function by either embedding its code as a query-defined function, or creating it as a stored function in your database, as follows:

Query-defined

Define the function using the following let statement. No permissions are required.

let normality_test_fl = (tbl:(*), data:string, test_statistic:string, p_value:string)
{
    let kwargs = bag_pack('data', data, 'test_statistic', test_statistic, 'p_value', p_value);
    let code = ```if 1:
        from scipy import stats
        data = kargs["data"]
        test_statistic = kargs["test_statistic"]
        p_value = kargs["p_value"]
        def func(row):
            statistics = stats.normaltest(row[data])
            return statistics[0], statistics[1]
        result = df
        result[[test_statistic, p_value]]  = df.apply(func, axis=1, result_type = "expand")
    ```;
    tbl
    | evaluate python(typeof(*), code, kwargs)
};
// Write your query to use the function here.

Stored

Define the stored function once using the following .create function. Database User permissions are required.

.create-or-alter function with (folder = "Packages\\Stats", docstring = "Normality Test")
normality_test_fl(tbl:(*), data:string, test_statistic:string, p_value:string)
{
    let kwargs = bag_pack('data', data, 'test_statistic', test_statistic, 'p_value', p_value);
    let code = ```if 1:
        from scipy import stats
        data = kargs["data"]
        test_statistic = kargs["test_statistic"]
        p_value = kargs["p_value"]
        def func(row):
            statistics = stats.normaltest(row[data])
            return statistics[0], statistics[1]
        result = df
        result[[test_statistic, p_value]]  = df.apply(func, axis=1, result_type = "expand")
    ```;
    tbl
    | evaluate python(typeof(*), code, kwargs)
}

Example

The following example uses the invoke operator to run the function.

Query-defined

To use a query-defined function, invoke it after the embedded function definition.

let normality_test_fl = (tbl:(*), data:string, test_statistic:string, p_value:string)
{
    let kwargs = bag_pack('data', data, 'test_statistic', test_statistic, 'p_value', p_value);
    let code = ```if 1:
        from scipy import stats
        data = kargs["data"]
        test_statistic = kargs["test_statistic"]
        p_value = kargs["p_value"]
        def func(row):
            statistics = stats.normaltest(row[data])
            return statistics[0], statistics[1]
        result = df
        result[[test_statistic, p_value]]  = df.apply(func, axis=1, result_type = "expand")
    ```;
    tbl
    | evaluate python(typeof(*), code, kwargs)
};
datatable(id:string, sample1:dynamic) [
'Test #1', dynamic([23.64, 20.57, 20.42, 27.1, 22.12, 33.56, 23.64, 20.57]),
'Test #2', dynamic([20.85, 21.89, 23.41, 35.09, 30.02, 26.52, 20.85, 21.89]),
'Test #3', dynamic([20.13, 20.5, 21.7, 22.02, 32.2, 32.79, 33.9, 34.22, 20.13, 20.5])
]
| extend test_stat= 0.0, p_val = 0.0
| invoke normality_test_fl('sample1', 'test_stat', 'p_val')

Stored

datatable(id:string, sample1:dynamic) [
'Test #1', dynamic([23.64, 20.57, 20.42, 27.1, 22.12, 33.56, 23.64, 20.57]),
'Test #2', dynamic([20.85, 21.89, 23.41, 35.09, 30.02, 26.52, 20.85, 21.89]),
'Test #3', dynamic([20.13, 20.5, 21.7, 22.02, 32.2, 32.79, 33.9, 34.22, 20.13, 20.5])
]
| extend test_stat= 0.0, p_val = 0.0
| invoke normality_test_fl('sample1', 'test_stat', 'p_val')

Output