RuneScape:Grand Exchange Market Watch/Adjustments (March 2012)

For 4 days on March 2012 (23, 24, 25 and 26 March), the Grand Exchange Database failed to produce the actual data for prices, incorrectly showing the prices for 22 March throughout the period. Hence, by using the prices for 22 and 27 March, the prices for the four days must be approximated and adjusted.

To approximate the prices, we use the average of closest prices (22 and 27 March).

The formula for the k-th missing price is as follows:


 * $${p}_{\text{k}} = {p}_{\text{start}} + \frac{{p}_{\text{end}} - {p}_{\text{start}}}{({d}_{\text{end} \to \text{start}})} \times ({d}_{\text{k} \to \text{start}})$$

For example, if the price for Item A is 331 coins on 22 March and 292 coins on 27 March, then the price for 24 March would be:


 * $$\begin{align}

{p}_{\text{24Mar}} &= {p}_{\text{22Mar}} + \frac{{p}_{\text{27Mar}} - {p}_{\text{22Mar}}}{({d}_{\text{27Mar} \to \text{22Mar}})} \times ({d}_{\text{24Mar} \to \text{22Mar}}) \\ \\

&= 331 + \frac{292-331}{5} \times 2 \\ \\

&= 315.4 = 315 \; \text{(rounded to nearest coin)}

\end{align}$$

Thus, the prices for the entire missing period would be as follows: