In a study, the cost overruns/underruns for 6 rail projects in the percentage of the original cost have been collected as follows: 6%, 9.2%, -0.5%, 7.1%, 10.3%, 4.2%. What is the mean and standard deviation of this sample respectively?
- 6.22% and 3.55%
- 6.05% and 3.88%
- 6.22% and 0.13%