In a recent survey, the proportion of adults who indicated mystery as their favorite type of book was 0. 325. Two simulations will be conducted for the sampling distribution of a sample proportion from a population with a true proportion of 0. 325. Simulation a will consist of 1,500 trials with a sample size of 100. Simulation b will consist of 2,000 trials with a sample size of 50. Which of the following describes the center and variability of simulation a and simulation b?.