An annual survey of public opinion considers the public views about adequacy of policies taken to protect global environment, with a random sample of about 5000 adults from each of 20 developing nations each year. In 2000, 15% of them expressed positive views about adequacy of the measures taken at the global level. In 2016, 75% of them expressed a positive attitude about the same.

(a) Explain what it would mean for these results to be based on (i) independent samples, (ii) dependent samples.

(b) If we compare results in 2000 and 2016, identify the response variable and the explanatory variable, and specify whether the response variable is quantitative or categorical.