Jawarrior1: Created page with "Indices must be adapted constantly to changing conditions so they can fulfill their purpose as measuring instruments for the Grand Exchange Market Watch. This page is meant to show the calculations for the adjustments made to the indices. For more information, see Grand Exchange Market Watch/FAQ. ==Common Trade Index== ===12 February 2012=== The CTI was adjusted on 12 February 2012 with the removal of six items (Mithril ore, Law rune, Big bones, R..."

2024-02-15T04:09:36Z

Created page with "Indices must be adapted constantly to changing conditions so they can fulfill their purpose as measuring instruments for the Grand Exchange Market Watch. This page is meant to show the calculations for the adjustments made to the indices. For more information, see Grand Exchange Market Watch/FAQ. ==Common Trade Index== ===12 February 2012=== The CTI was adjusted on 12 February 2012 with the removal of six items (Mithril ore, Law rune, Big bones, R..."

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Indices must be adapted constantly to changing conditions so they can fulfill their purpose as measuring instruments for the [[Grand Exchange Market Watch]]. This page is meant to show the calculations for the adjustments made to the indices. For more information, see [[Grand Exchange Market Watch/FAQ]].

==Common Trade Index==
===12 February 2012===

The CTI was adjusted on 12 February 2012 with the removal of six items ([[Mithril ore]], [[Law rune]], [[Big bones]], [[Raw swordfish]], [[Vial of water]], [[Clean ranarr]]) and the addition of 10 items ([[Abyssal whip]], [[Dragon boots]], [[Rune armour set (lg)]], [[Red chinchompa]], [[Oak plank]], [[Shark]], [[Green dragonhide]], [[Dragon bones]], [[Cannonball]], [[Dragonfire shield]]). This brought the total of items in the CTI to 27 items.

{| class="wikitable collapsible collapsed" style="width:300px"
! colspan="3" | List of items and prices
|-
! Item
! Base price
! Price on 12-Feb-2012
|-
| Coal || 159 || 320
|-
| Steel bar || 540 || 1,335
|-
| Gold ore || 528 || 304
|-
| Mithril ore || 315 || 349
|-
| Nature rune || 271 || 226
|-
| Death rune || 299 || 452
|-
| Law rune || 303 || 363
|-
| Pure essence || 80 || 125
|-
| Yew logs || 411 || 522
|-
| Magic logs || 1,222 || 1,592
|-
| Cowhide || 109 || 513
|-
| Big bones || 419 || 621
|-
| Raw lobster || 237 || 285
|-
| Raw swordfish || 325 || 492
|-
| Raw monkfish || 350 || 601
|-
| Flax || 70 || 72
|-
| Soft clay || 207 || 541
|-
| Limpwurt root || 646 || 2,060
|-
| Snape grass || 428 || 314
|-
| Vial of water || 98 || 36
|-
| Clean ranarr || 5,959 || 4,958
|-
| Clean snapdragon || 6,885 || 9,866
|-
| Clean kwuarm || 3,030 || 1,828
|-
| Abyssal whip || – || 420,951
|-
| Dragon boots || – || 103,701
|-
| Rune armour set (lg) || – || 136,531
|-
| Red chinchompa || – || 1,592
|-
| Oak plank || – || 639
|-
| Shark || – || 1,715
|-
| Green dragonhide || – || 2,196
|-
| Dragon bones || – || 3,962
|-
| Cannonball || – || 407
|-
| Dragonfire shield || – || 7,946,801
|}

With the removal and addition of several items, we need a new divisor:

:<math>{div}_{\text{new}} = {div}_{\text{old}} \times \frac{\sum \left ( \frac{p}{q} \right )_{\text{new}}}{\sum \left ( \frac{p}{q} \right )_{\text{old}}}</math>

And, to calculate the new divisor, we need to find:

:<math>\begin{align}
{div}_{\text{old}} & = 21.791759207424 \\

\sum \left ( \frac{p}{q} \right )_{\text{old}} & = \frac{320}{159} + \frac{1335}{540} + \frac{304}{528} + \dots + \frac{1862}{3030} = 35.26980062 \\

\sum \left ( \frac{p}{q} \right )_{\text{new}} & = \sum \left ( \frac{p}{q} \right )_{\text{old}} - \left ( \frac{349}{315} + \frac{363}{303} + \dots + \frac{4958}{5959} \right ) + \left ( \frac{420951}{420951} + \frac{103701}{103701} + \dots + \frac{7946801}{7946801} \right ) = 38.76853218
\end{align}</math>

Thus, the new divisor is:

:<math>{div}_{\text{new}} = 21.791759207424 \times \frac{38.76853218}{35.26980062} = 23.9535</math>

==See also==
* [[Grand Exchange Market Watch/FAQ]]
* [[Template:GE Common Trade Index]]

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[[Category:Grand Exchange]]

Grand Exchange Market Watch/Index adjustments - Revision history