Name the quantity being reduced
Sample rate describes samples per second. Delivery bitrate describes bits per second. The relationship depends on the representation and encoding choices. A lower sample-rate number alone is not a measured traffic result for a compressed file.
For an owned derivative, record the codec settings, channels, sample rate, actual bytes and duration before comparing versions. Keep source and destination content equivalent. A shorter file can be smaller because it lost material rather than because it encoded more efficiently.
Avoid extending a PCM storage calculation to every compressed format. A codec's selected bitrate or quality mode is a separate decision, and the container adds its own data.
Compare the completed outputs
Choose a bounded source passage with representative sound and produce only the candidates the delivery decision needs. Inspect their actual size and duration, then review sound quality and required destination support. This is a proposed comparison, not an encoding test performed here.
If the output size barely changes, do not describe the lower sample rate as a demonstrated bandwidth saving. If it does shrink, record which settings changed and check that the result still serves the audience. Several changed controls make the cause less certain.
Digital audio concepts by Mozilla Contributors is available under CC-BY-SA 2.5 or later. The comparison method is original guidance. Keep the final report in concrete terms: measured output properties and reviewed listening result, with no universal promise that resampling alone makes a stream cheaper.
Questions answered
Does halving sample rate necessarily halve a compressed file's size?
No. Encoding, channels, duration and container choices also matter.
What evidence supports a traffic-saving claim?
Compare the actual equivalent outputs and state the conditions and measurement.
Sources & further reading
Official references for the subjects discussed. Service terms and device software can change.