Alejandro was curious if sample median was an unbiased estimator of population median. He placed ping pong balls numbered from 000 to 323232 in a drum and mixed them well. Note that the median of the population is 161616. He then took a random sample of 555 balls and calculated the median of the sample. He replaced the balls and repeated this process for a total of 505050 trials. His results are summarized in the dotplot below, where each dot represents the sample median from a sample of 555 balls. A dot plot for a sample median has a scale from 0 to 30. The number of dots for each is as follows. 0, 0. 1, 0. 2, 0. 3, 0. 4, 1. 5, 1. 6, 2. 7, 1. 8, 0. 9, 1. 10, 5. 11, 3. 12, 2. 13, 4. 14, 1. 15, 3. 16, 4. 17, 4. 18, 1. 19, 2. 20, 4. 21, 2. 22, 0. 23, 1. 24, 2. 25, 1. 26, 1. 27, 0. 28, 2. 29, 2. 30, 0. Based on these results, does sample median appear to be a biased or unbiased estimator of population median