What is the standard error in Python, and how is it calculated?

The standard error (SE) in Python, often calculated using libraries like SciPy or NumPy, measures the statistical accuracy of an estimate. It's the standard deviation of the sampling distribution of a statistic (usually the sample mean). It is typically calculated as the sample standard deviation divided by the square root of the sample size: SE = s / sqrt(n), where 's' is the sample standard deviation and 'n' is the sample size. Using NumPy: `import numpy as np; data = [1, 2, 3, 4, 5]; se = np.std(data) / np.sqrt(len(data))`.