Posted by Ion on Thursday, March 4, 2010 at 9:00am.
The USDA size standards for eggs are based on weight and are as follows:
SMALL: greater than 43 grams, less than 50 grams
MEDIUM: greater than 50 grams, less than 57 grams
LARGE: greater than 57 grams, less than 64 grams
EXTRA LARGE: greater than 64 grams, less than 71 grams
JUMBO: greater than 71 grams.
The output of a particular egg farm has a mean weight of 62 grams with a standard deviation of 8 grams. What is the percentage of egg output of this farm in each size category?

Statistics  PsyDAG, Thursday, March 4, 2010 at 10:16am
Z = (score  mean)/standard deviation
Small eggs are between 4350 grams.
(4362)/8 ≤ Small eggs ≤ (5062)/8
Look up these two z scores in table in back of your stat text labeled something like "areas under normal distribution" to find proportion between these two points. Convert to percentage.
Do the same with the other categories.
I hope this helps.