Anyone else noticed this?
To compute an average means adding up all transactions over a certain set (i.e., period of time, like 24 hours) and then divide that total by the number of transaction quantities occurring during that period of time.
So let's say right now the 24 hour total include just these:
2 BTC @ $49 (happened 23.75 hours ago)
2 BTC @ $48 (happened 23.50 hours ago)
2 BTC @ $36 (happened five hours ago)
Total of all transactions is $266, and involved the quantity of six BTC, so the 24 hour average is $44.33.
Then over the next hour there is only one more transaction that occurs, 2 @ 45. But the $49 and $48 transactions drop off as they no longer occurred within the last 24 hours.
So after that transaction has occurred then the next time I do the 24 hour average computation it has just:
2 BTC @ $36 (happened six hours ago)
2 BTC @ $45 (happened within the past hour)
Total of all transaction is $162, and involved the quantity of four BTC, so the 24 hour average is $40.50.
The average went down even though the "last" went up (from $36 to $45).