pandas.api.typing.Expanding.sem

Expanding.sem(ddof=1, numeric_only=False)

Calculate the expanding standard error of mean.

The standard error is computed as std / sqrt(N) over all data points seen so far, where N is the number of observations.

Parameters:

ddofint, default 1

Delta Degrees of Freedom. The divisor used in calculations is N - ddof, where N represents the number of elements.

numeric_onlybool, default False

Include only float, int, boolean columns.

Returns:

Series or DataFrame

Return type is the same as the original object with np.float64 dtype.

See also

Series.expanding

Calling expanding with Series data.

DataFrame.expanding

Calling expanding with DataFrames.

Series.sem

Aggregating sem for Series.

DataFrame.sem

Aggregating sem for DataFrame.

Notes

A minimum of one period is required for the calculation.

Examples

>>> s = pd.Series([0, 1, 2, 3])

>>> s.expanding().sem()
0         NaN
1    0.500000
2    0.577350
3    0.645497
dtype: float64