Salt intake

Inspired by the recent dietary guidelines (http://www.cnpp.usda.gov/dietaryguidelines.htm), I wanted to see how good people are at estimating the amount of salt in food. Below are box-plots of the percentage of one's daily recommended value of salt (based on a 2,000 calorie diet) people THOUGHT were contained in a serving size for the different foods. In addition to what people thought, the green squares represent the ACTUAL percentage of one's daily recommended value of salt.
















It is interesting that, people typically over-estimate the amount of salt included in the foods (except for the bagel and black beans), but at the same time, people thought our daily recommended value of salt is 5.43 grams while in reality it is 2.4 grams or 1 teaspoon.
N = 11

Items include (serving size):
Thomas plain bagel (1 bagel)
Bush's black beans (1/2 cup)
Campbell's tomato soup (1 cup)
Utz wheat n cheddar crackers (1 pkg)
Oscar Mayor bologna (1 slice)
Snyder's sourdough nibblers (16 nibblers)
Peter Pan crunchy peanut butter (2 tbsp)
Planters Lightly salted cashews (1 oz)
Oreo (3 cookies)