Calculating the sample mean

The late_shipments dataset contains supply chain data on the delivery of medical supplies. Each row represents one delivery of a part. The late columns denotes whether or not the part was delivered late. A value of "Yes" means that the part was delivered late, and a value of "No" means the part was delivered on time.

You'll begin your analysis by calculating a point estimate (or sample statistic), namely the proportion of late shipments.

In pandas, a value's proportion in a categorical DataFrame column can be quickly calculated using the syntax:

prop = (df['col'] == val).mean()

late_shipments is available, and pandas is loaded as pd.