RuneScape:Grand Exchange Market Watch/Adjustments (8 November 2013)

8 November 2013

Adjusted index: Log Index Adjustment date: 8 November 2013 Affected templates: Template:GE Log Index and Template:GE Log Index/Diff Added item(s): Elder logs Removed item(s): None Items before adjustment: 10 Items after adjustment: 11 Divisor before adjustment: 10.0000 Divisor after adjustment: 10.3117 Item Base date Base price Price on adjustment date Comments Logs 19 December 2007 34 28 Unchanged Achey tree logs 40 39 Oak logs 18 12 Willow logs 22 20 Teak logs 136 71 Maple logs 46 30 Mahogany logs 173 392 Arctic pine logs 855 57 Yew logs 413 526 Magic logs 1,221 1,646 Elder logs – – 3,952 Added item Calculations From the old divisor obtained from the templates: ${div}_{\text{old}} = 10.0000$ 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: $\begin{align} \sum \left ( \frac{p}{q} \right )_{\text{old}} & = \text{sum of ratios prior to change} \\ & = \frac{280}{34} + \frac{399}{40} + \frac{123}{18} + \dots + \frac{1,646}{1,221} \\ & = 32.08119681 \text{ (up to 8 d.p.)} \end{align}$ And also: $\begin{align} \sum \left ( \frac{p}{q} \right )_{\text{new}} & = \text{sum of ratios prior to change} - \text{sum of removed ratios} + \text{sum of added ratios} \\ & = \sum \left ( \frac{p}{q} \right )_{\text{old}} - \text{sum of removed ratios} + \text{number of added items} \\ & = 32.08119681 - 0 + 1 \\ & = 33.08119681 \text{ (up to 8 d.p.)} \end{align}$ Thus, the new divisor is: $\begin{align} {div}_{\text{new}} & = {div}_{\text{old}} \times \frac{\sum \left ( \frac{p}{q} \right )_{\text{new}}}{\sum \left ( \frac{p}{q} \right )_{\text{old}}} \\ & = 10.0000 \times \frac{33.08119681}{32.08119681} \\ & = 10.3117 \text{ (4 d.p.)} \end{align}$