this is an interesting problem but ... to me, the more important matter is JUST HOW YOU WILL DO THE SAMPLING?
orchards i am familiar with are not all in the same place (one part might be on the right side of the road ... the other part on the left side of the road) and, there typically are narrow paths separating rows of trees ...
there are several possible strata here ... side of road ... tree rows ... etc. ... so, will you be attempting to take a stratified RANDOM sample?
let's say that you do identify side of road and row ... as strata ... then, how will you do the actually sampling from selected TREES? i am trying to visualize in my head ... how you would take a random orange from a tree??? perhaps you will need a cluster sampling plan ... select the trees and then take ALL oranges from the selected trees ...
the ns you need to have estimates be "within" some margin of error ... are partly a function of the exact sampling method (i don't see any way you can take a random sample here) ... how much variability there really is in the # of seeds in oranges ... and, the confidence you want to have for the level of accuracy (margin of error) you want
i just hope that citrus canker doesn't set in before you get your sampling done!
for starters though ... can you give us some idea of the RANGE of # of seeds you might expect to find ... across a bunch of oranges?
_________________________________________________________Background: We are an orange grower and this problem relates to seeds in oranges. Our goal is to provide our customers with seedless oranges but the nature of oranges is that they typically have seeds. Growing practices, climate changes (too much rain, too little sun�) effects if a seed forms in an orange. I envision sampling an orchard prior to harvesting to get an accurate assessment of the % of oranges that contain seeds. A single orchard might have 1000 trees @ 100 oranges per tree (100,000 oranges per orchard). The grading would be perform by cutting an orange open and inspecting it for seeds and placing it into one of two categories � contains seeds or is seedless.Goal: I want to create a sampling program that will determine at the confidence levels above that the oranges we are providing are seedless. I have a couple of semesters of college statistics but it has been a long time since I have used any of it. Could you please describe how I can calculate a sample size with its corresponding confidence interval for the sampling goal stated above? I want to be able to say something similar to - "I am 95% confident that 2% of the oranges in this orchard have seeds" . . ================================================================= Instructions for joining and leaving this list, remarks about the problem of INAPPROPRIATE MESSAGES, and archives are available at: . http://jse.stat.ncsu.edu/ . =================================================================
dennis roberts, educational psychology, penn state university
208 cedar, AC 8148632401, mailto:[EMAIL PROTECTED]
http://roberts.ed.psu.edu/users/droberts/drober~1.htm
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