The 2016 Minneapolis Resident Survey was a questionnaire that the City of Minneapolis issued to its randomly chosen residents. In this survey, 1,155 of the 2,307 respondents (50.1%) rated their neighborhood as a very good place to live. After adjusting for the demographic characteristics of the population, the City of Minneapolis concluded with 95% confidence that the true proportion of all residents considering their neighborhood as a very good place to live is between 0.44 and 0.50. Which of the following statements are correct?
i. The Minneapolis Resident Survey was an observational study.
ii. The Minneapolis Resident Survey was an experiment.
iii. The figure 50.1% is a descriptive statistic for the sample.
iv. The figure 50.1% is a statistical inference for the population.
a) i. and iii.
b) i. and iv.
c) ii. and iii.
d) ii. and iv.

We observe in the case provided that the researcher, who has no interest in the population to intervene, is going to carry out surveys to assess whether the neighborhood is a good place to live, obtaining the following conclusions:

i. The Minneapolis Resident Survey was an observational study.

ii. The Minneapolis Resident Survey was an experiment.

iii. The figure 50.1% is a descriptive statistic for the sample.

iv. The figure 50.1% is a statistical inference for the population.:By estimating the sample, obtained by a lower percentage of the total of the respondents, it is known that with a 95% confidence interval that the rating obtained from the respondents considering that the neighborhood is a good place to live was found between 0.44 and 0.50, taking this interval as a statistical inference for the population.

The correct answer is I and III, since in this study no interventions were made to the population and only one observation of a characteristic of the neighborhood was made and in III we know that the descriptive statistic only describes data and summarizes it, which is a of the ways to display the data from the descriptive survey.