THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
In a recent survey of consumer confidence,160 respondents were classified by their level of education.The results of the survey are presented below.
-What is the proportion of respondents who had medium or high confidence?
A)0.330
B)0.271
C)0.719
D)0.670

Question

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
In a recent survey of consumer confidence,160 respondents were classified by their level of education.The results of the survey are presented below. 
-What is the proportion of respondents who had medium or high confidence?
A)0.330 
B)0.271 
C)0.719 
D)0.670

Quizplus · Accepted Answer

The proportion of respondents who had medium or high confidence can be calculated by adding the percentages for "medium" and "high" confidence together. This equals 39.4% + 28.3% = 67.7%, which is equivalent to 0.677 or 0.670 rounded to three decimal places. Therefore, the best choice is C.