A Wine Magazine Wants to Know If Chefs Can Tell

Multiple Choice

A wine magazine wants to know if chefs can tell the difference between duck liver pâté and wet dog food. Eighteen chefs were asked to rate both the pâté and dog food on a scale from 1 to 5, with 1 corresponding to "inedible" and 5 to "very tasty." The results are shown in the following table. The estimate of the population proportion of plus signs is ________.

A) 0.944
B) 0.50
C) 0.056
D) None of these choices is correct.