The Food and Drug Administration will allow a food
product to be labeled “sodium free” only if there is strong
evidence that it contains, on average, less than 5 milligrams of
sodium per serving. A soft drink producer, wishing to use a “salt
free” label, has its product tested. A laboratory takes 25
independent sample servings of the soft drink and measures them for
sodium content using a technique that is practically free of bias.
These measurements average 4.9 milligrams...