Acme Foods wants to make its chips saltier, but it doesn't want to spend more than it has to on salt. A sample of consumers are asked to compare its current chip (saltiness = 100) with saltier versions and to say whether the new version is saltier. On average, sample consumers reliably say the new chip is saltier when its saltiness value is 108, but not when its saltiness value is below 108. Assuming Acme Foods' sample consumers are representative of people in general, which of the following best represents the just noticeable difference for saltiness?
8%