Answer:
According to the empirical rule (also known as the 68-95-99.7 rule), for a bell-shaped distribution, approximately:
- 68% of the data falls within one standard deviation of the mean.
- 95% falls within two standard deviations of the mean.
- 99.7% falls within three standard deviations of the mean.
In this case, the mean number of phone calls answered by each receptionist is 36, and the standard deviation is 3.
To calculate the percentage of daily phone calls numbering between 33 and 39, we need to find the proportion of data within one standard deviation of the mean in either direction.
The range of interest (33 to 39) is within one standard deviation of the mean, so approximately 68% of the data will fall within this range.
Therefore, the approximate percentage of daily phone calls numbering between 33 and 39 is 68%.