In March 2015, the Public Policy Institute of California (PPIC) surveyed 7525 likely voters living in California. This is the 148th PPIC research poll and is part of a survey series that started in 1998. PPIC researchers find that 3266 survey participants are registered Democrats and 2137 survey participants are registered Republicans. PPIC is interested in the difference between the proportion of registered Democrats and the proportion of registered Republicans in California. Which of the following correctly describe the 90% confidence interval to estimate the difference between registered Democrats and registered Republicans in California? Check all that apply.
a. If researchers repeat the survey many times, the true difference between registered Democrats and registered Republicans in California will be in the interval 90% of the time.
b. If researchers repeat the survey many times, there is a 90% chance that the true sample difference between registered Democrats and registered Republicans in California will be in the 90% confidence interval.
c. Researchers calculated the difference between registered Democrats and registered Republicans in California using a method that gives correct results 90% of the time.