  
| Author: | wildchicken13  | | Posted: | Nov 17, 2020 01:17 | | Subject: | Re: standard deviation on price indices | | Viewed: | 39 times | | Topic: | Suggestions | |
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| In Suggestions, brick_projects writes:
| | Please implement standard deviation.
By eliminating the (small number)% cheapest and (small number) % most expensively
priced lots, the average price index would be "more statistically significant"
in scientific terms ( less error margin ).
This is only necessary for items that have at least e.g. 10 distinct lots for
sale.
Why this suggestion ?
Yesterday i noticed one particular seller set all his prices at ( BL avg x 10000
). This caused average price index "lots for sale" to be inflated at least
tenfold.
Someone else suggested he made a mistake in currency.
If this one shopkeeper persists, unwanted "extreme" inflation may occur on several
very common items, and those lots - for sellers not paying attention when adding
to their inventory - might become impossible to sell.
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Rather than excluding data points from the calculation of the mean, why not add
a median to the price guide? The median is much more resilient to outliers like
the example you gave. Both the mean and the median provide useful information,
especially when they are different.
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Message is in Reply To:  standard deviation on price indices - brick_projects (3656) | Please implement standard deviation. By eliminating the (small number)% cheapest and (small number) % most expensively priced lots, the average price index would [...]
(96 months ago, Jul 20, 2016, to Suggestions) |
21 Messages in this Thread: Msg 1 - brick_projects (3656) 96 months ago Jul 20, 2016 to Suggestions
 Msg 2 - FigBits (3564) 96 months ago Jul 20, 2016 to Suggestions
  Msg 3 - jeslego (1050) 96 months ago Jul 20, 2016 to Suggestions
Msg 4 - FigBits (3564) 96 months ago Jul 20, 2016 to Suggestions
Msg 5 - yorbrick (1185) 96 months ago Jul 20, 2016 to Suggestions
Msg 6 - FigBits (3564) 96 months ago Jul 20, 2016 to Suggestions
Msg 7 - jeslego (1050) 96 months ago Jul 20, 2016 to Suggestions
Msg 8 - FigBits (3564) 96 months ago Jul 20, 2016 to Suggestions
Msg 9 - jedvii (666) 96 months ago Jul 22, 2016 to Suggestions
Msg 10 - yorbrick (1185) 96 months ago Jul 20, 2016 to Suggestions
Msg 11 - jancg (378) 96 months ago Jul 20, 2016 to Suggestions
Msg 12 - ToddMyers (356) 96 months ago Jul 20, 2016 to Suggestions
Msg 13 - jancg (378) 96 months ago Jul 20, 2016 to Suggestions
Msg 14 - Leftoverbricks (2225) 96 months ago Jul 20, 2016 to Suggestions
Msg 15 - garbanzo (322) 96 months ago Jul 20, 2016 to Suggestions
Msg 16 - jancg (378) 96 months ago Jul 20, 2016 to Suggestions
Msg 17 - yorbrick (1185) 96 months ago Jul 20, 2016 to Suggestions
Msg 18 - ToriHada (8887) 96 months ago Jul 20, 2016 to Suggestions
Msg 19 - Made_In_Bricks (3994) 96 months ago Jul 20, 2016 to Suggestions
Msg 20 - FigBits (3564) 96 months ago Jul 20, 2016 to Suggestions
Msg 21 « - wildchicken13 (876) 43 months ago Nov 17, 2020 to Suggestions
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USA, Illinois
