One of the more popular statistics reporters in the president's job approval rating. the approval rating is reported as the proportion of the population who approve of the job that the sitting president is doing and is typically based on a random sample of registered voters complete parts (a) and (b) below this proportion tends to fluctuate from week to week name some reasons for the fluctuation in the statistic select all valid reasons below the proportion could be changing because people's attitudes are changing.. the proportion could be changing due to sampling error, different people are in the sample the proportion could be changing due to a large change in the composition of the population the proportion could be changing because the sampling size of the poll is changing