Which of the following best describes the function of a parity bit?

The function of a parity bit is to provide a simple method for error checking in transmitted or stored data. A parity bit is an extra bit added to a binary value that ensures that the total number of 1-bits in the value is even (even parity) or odd (odd parity). When data is transmitted, the sender calculates the parity and sends the data along with the parity bit. The receiver then recalculates the parity based on the received data and compares it with the received parity bit. If there is a discrepancy, it indicates that an error has occurred during transmission.

This basic error detection mechanism allows for quick verification of data integrity. If the computed parity at the receiving end does not match the parity bit sent by the sender, it signals that the data may have been altered or corrupted, prompting a request for retransmission or error handling.

The other options do not accurately describe the function of a parity bit. While data size relates to the overall structure of the data, encoding pertains to transforming data into a different format for transmission, and compression refers to reducing the size of data for storage, none of these processes involve the error-checking role of a parity bit.