As a new feature on the Forum, I have added Volume-Weighted TRIN to the Pages menu on the right-hand side of the Forum.
The TRIN (Short-Term TRading INdex) or Arms Index (discovered by Richard Arms in 1967) is the ratio of advancing to declining issues divided by the ratio of advancing to declining volume. As a breadth oscillator, it can be used as an overbought-oversold indicator.
The 5-day average TRIN is a popular way to smooth the indicator. You simply add the final daily TRIN for each of the last 5 days and divide by 5. Accordingly, each day counts the same in the 5-day simple TRIN average.
Some people prefer to use a 5-day exponential moving average of TRIN, which weighs the TRIN days in order of recency.
However, neither method accounts for volume. I will update the Volume-Weighted TRIN chart on a weekly basis, and will update the TRIN data daily.