4. A political scientist is interested in seeing if political party affiliation is related to whether or not people read the daily newspaper. Using a telephone survey of 400 randomly selected registered voters, he solicits both their party identification and whether or not they had read the newspaper that day. The results are displayed in the following cross-tabulation: Read Paper Yes No Total Registered Democrat 64 96 160 Republican 49 91 140 Independent 31 69 100 Total 144 256 400 a. Which is the independent variable, and which is the dependent variable? b. Calculate and interpret the appropriate (and only the appropriate) percentages for the cross-tabulation