The General Social Survey is conducted every year and asks a variety of questions to a representative sample of non-institutionalized adults in the United States. In 2014, the survey showed that 417 out of 2,538 respondents said they read a newspaper every day. Twenty years earlier, in 1994, the survey showed that 969 out of the 2,992 respondents said they read a newspaper every day. We want to calculate a 90% confidence interval for the difference in the proportions in the population who read the paper every day in 2014 compared to 1994. 

a. Describe the parameter we want to estimate and assign appropriate symbols to it. 

b. Are the validity conditions met here for theory-based methods? Explain. 

c. Determine the 90% confidence interval. 

d. Interpret the confidence interval you obtained in the context of the study