Twenty air samples were obtained and the carbon monoxide concentrations were recorded. the results in ppm (parts per million) were:
9.3 10.7 8.5 9.6 12.2 15.6 9.2 10.5 9.0 13.2
11.0 8.8 13.7 12.1 9.8 10.5 11.2 9.9 12.4 10.9
(a) Calculate the mean, the median and the standard deviation.(b) Obtain the mean , the median, and the standard deviation in the units parts per thousand without recalculating everything from scratch.