Because the distribution of sample proportions based on samples of size n = 50 is approximately Normal, with a mean of 0.50 and a standard deviation of 0.07], we can apply the Empirical Rule. :l ' Approximately 68% of the sample proportions are between what two values? " Approximately 95% of the sample proportions are between what two values? ' Approximately 99.7% of the sample proportions are between what two values? a D