One of the PewResearchCenter’s survey topics is mobile phone use. The file “Riverside_Smartphone_Dependency” summarizes the proportion of respondents who are smartphone dependent (use smartphones as their primary means of online access at home) in the County of Riverside, California.

a) In 2016, what is the sample proportion of adults in the County who are smartphone dependent?
b) In 2016, which group showed the highest smartphone dependent?
c) How does income appear to affect smartphone dependency?