## FANDOM

41,547 Pages

The Food Index is made up of a weighted average of all of the current foods listed in the Market Watch, with the starting date of this average on 12 January 2008, at an index of 100. The overall rising and falling of food prices is reflected in this index.

While specialised for just watching food prices, it is set up and adjusted in a manner similar to the Common Trade Index, and the divisor may be adjusted to include new food added by Jagex (see the FAQ for more information).

As of today, this index is 322.52  -3.47

## SummaryEdit

Any suggested changes to this index should be added to the talk page.

• Start date: 12 January 2008 (at index of 100)
• Index today: 322.52
• Change today:  -3.47
• Number of items: 19 (last adjusted on 12 January 2008)
• Index divisor: 19.0000 (last adjusted on 12 January 2008)

## List of itemsEdit

This is the current list of items included in this index:

Icon Item Price Direction Low Alch High Alch Limit Members Details Last updated
Bass168
10816210,000view56 minutes ago
9141,000view33 minutes ago
Cake452
20301,000view23 minutes ago
Cavefish1,873
14021010,000view18 minutes ago
Chocolate cake813
28421,000view14 minutes ago
Great white shark1,166
13019510,000view18 hours ago
Lobster92
10716010,000view17 hours ago
Monkfish357
9213810,000view17 hours ago
Rocktail2,190
24036010,000view15 hours ago
Salmon39
355210,000view15 hours ago
801201,000view15 hours ago
Shark1,031
12018010,000view15 hours ago
Strawberries (5)646
0010,000view14 hours ago
Swordfish202
16024010,000view14 hours ago
Tuna36
487210,000view14 hours ago

20 May 2015
Item Base date Base price Price on adjustment date Comments
Lobster 25 January 2008 175 196 Unchanged
Bass 195 225
Tuna 81 163
Swordfish 272 295
Monkfish 233 336
Shark 657 739
Cake 52 91
Chocolate cake 150 421
Ugthanki kebab 887 810 Removed item
Kebab 32 276
Sea turtle 1,264 2,690
Manta ray 1,794 1,907
Sweetcorn 135 43
Roast bird meat 22 19
Admiral pie 1,031 497
Wild pie 3,491 985
Redberry pie 381 1,280
Garden pie 657 475
Stew 100 1,102
Strawberries (5) 318
Saradomin brew (4) 9,762
Salmon 80
Cavefish 1,256
Rocktail 1,814
Great white shark 912

Calculations

From the old divisor obtained from the templates:

${div}_{\text{old}} = 19.0000$

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} \\ & = \text{sum of unchanged ratios} + \text{sum of removed ratios} \\ & = \left (\frac{196}{175} + \frac{225}{195} + \dots + \frac{421}{150} \right ) + \left (\frac{810}{887} + \frac{276}{32} + \dots + \frac{1,102}{100} \right ) \\ & = 42.27255853 \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} \\ & = 42.27255853 - \left ( \frac{810}{887} + \frac{276}{32} + \dots + \frac{1,102}{100} \right ) + 7 \\ & = 19.49428715 \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}}} \\ & = 19.0000 \times \frac{42.27255853}{19.49428715} \\ & = 8.7619 \text{ (4 d.p.)} \end{align}