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The question 鈥淪hould guys pay for the first date?鈥� was posted in the electronic version of a newspaper, where 1148 respondents chose to respond, and 85% of them said yes.

a.

The subjects are known to respond to the survey through an electronic version of the newspaper by the mode of voluntary participation.

As it is voluntary participation, the sample is known to be a voluntary response sample. Such a sample is not a true representative of the population.

Thus, the wrong in the study is that the sample is a voluntary response sample.

b.

A statistic is different from a parameter value of any measure. The statistic is always obtained from sample observations, while the parameter is the value of the measure obtained from all observations of the population.

85% is a proportion measure obtained from 1148 participants in the study.

Thus, 85% is a statistic.

c.

An observational study involves responses from participants when they are not exposed to any treatment. On the other hand, an experiment gathers responses when the participants receive some kind of treatment.

In this case, the subjects are simply asked for the responses; rather than being exposed to any treatment.

Thus, it is an observational study.