RuneScape:Grand Exchange Market Watch/Adjustments (6 November 2011)

6 November 2011

Adjusted index: Herb Index Adjustment date: 6 November 2011 Affected templates: Template:GE Herb Index and Template:GE Herb Index/Diff Added item(s): Grimy fellstalk, Clean fellstalk Removed item(s): None Items before adjustment: 32 Items after adjustment: 34 Divisor before adjustment: 32.0000 Divisor after adjustment: 33.2409 Item Base date Base price Price on adjustment date Comments Grimy guam 9 June 2009 490 121 Unchanged Grimy marrentill 192 25 Grimy tarromin 216 121 Grimy harralander 787 100 Grimy ranarr 7,654 4,032 Grimy toadflax 2,315 3,637 Grimy irit 1,552 1,172 Grimy wergali 1,800 2,450 Grimy spirit weed 1,917 2,658 Grimy avantoe 1,591 3,293 Grimy kwuarm 2,850 1,356 Grimy snapdragon 9,720 5,224 Grimy cadantine 1,234 1,186 Grimy lantadyme 1,272 5,006 Grimy dwarf weed 2,042 4,744 Grimy torstol 2,980 25,300 Clean guam 481 126 Clean marrentill 101 16 Clean tarromin 193 143 Clean harralander 791 100 Clean ranarr 7,719 3,867 Clean toadflax 2,362 3,644 Clean irit 1,795 1,232 Clean wergali 2,000 2,331 Clean spirit weed 1,888 2,725 Clean avantoe 1,593 3,253 Clean kwuarm 2,881 1,389 Clean snapdragon 9,726 5,402 Clean cadantine 1,245 1,206 Clean lantadyme 1,319 5,267 Clean dwarf weed 2,070 4,668 Clean torstol 2,762 25,400 Grimy fellstalk – – 1,799 Added item Clean fellstalk 1,437 Calculations From the old divisor obtained from the templates: ${div}_{\text{old}} = 32.0000$ We need to calculate a new divisor: ${div}_{\text{new}} = {div}_{\text{old}} \times \frac{\sum \left ( \frac{p}{q} \right )_{\text{new}}}{\sum \left ( \frac{p}{q} \right )_{\text{old}}}$ To calculate the new divisor, we need to find: $\begin{align} \sum \left ( \frac{p}{q} \right )_{\text{old}} & = \text{sum of ratios prior to change} \\ & = \frac{121}{490} + \frac{25}{192} + \frac{121}{216} + \dots + \frac{25,400}{2,762} \\ & = 51.57722802 \text{ (up to 8 d.p.)} \end{align}$ And also: $\begin{align} \sum \left ( \frac{p}{q} \right )_{\text{new}} & = \text{sum of ratios prior to change} - \text{sum of removed ratios} + \text{sum of added ratios} \\ & = \sum \left ( \frac{p}{q} \right )_{\text{old}} - \text{sum of removed ratios} + \text{number of added items} \\ & = 51.57722802 - 0 + 2 \\ & = 53.57722802 \text{ (up to 8 d.p.)} \end{align}$ Thus, the new divisor is: $\begin{align} {div}_{\text{new}} & = {div}_{\text{old}} \times \frac{\sum \left ( \frac{p}{q} \right )_{\text{new}}}{\sum \left ( \frac{p}{q} \right )_{\text{old}}} \\ & = 32.0000 \times \frac{53.57722802}{51.57722802} \\ & = 33.2409 \text{ (4 d.p.)} \end{align}$