When writing questions for a questionnaire, have each item refer to only one single thing per question. Otherwise, the response may be ambiguous in meaning. It is generally better to use a previously established and validated measure than to develop a new one for yourself Ratio level variables are usually counting variables or quantity measures, how many or how much. When developing a measure of a concept that has polar opposites, such as love versus hate, use the same adjectives at each end. It will produce a more balanced measure.
Variables always have more than one characteristic, attribute, or quality to which they refer.
Constants do not. Every research question can be stated as an hypothesis, and vice versa. It is easier to discuss a problem given a single research question than to derive a research question from a discussion of a problem. Research problems have to be stated as questions about facts,not about moral judgments. Systematic sampling was early used in Persia in its war with Greece.