Developing a questionnaire is considered "part art and part science." Which of the following is a good practice for questionnaire creation? a. Questions are better when they are open to multiple interpretations.
b. Layout of the questionnaire should test the respondent's ability follow instructions.
c. Questions should be designed to address a specific set of research questions.
d. The questions should use hard-to-understand language.

What is the difference between total utility and marginal utility? a. marginal utility is subject to the law of diminishing marginal utility while total utility is not. b. total utility represents the consumer optimum while marginal utility gives the total utility per dollar spent on the last unit. c. total utility is the total amount of satisfaction derived from consuming a certain amount of a good while marginal utility is the additional satisfaction gained from consuming an additional unit of the good. d. marginal utility represents the consumer optimum while total utility gives the total utility per dollar spent on the last unit.