How do I work out how to find the new sample mean when you have a sample size of 20, the mean is 12, the data is bimodal with modes of 10 and 17 and the median is 14. After this has all been calculated a new item of data has been found, being of value 17, which needs to be added to the sample. So now the sample size is 21 and I was able to work out the new mean is 12.24 by using the equation - but I can't work out what the new median would be.