Please consider these data points as an example of many more, they represent single studies with multiple samples which have been done during the last decades.
7.7 +/-3.3) mg/L, n=10
3.6 +/-0.2 mg/L, n=22
The publication states that 7.7 resp. 3.6 represents mean OR median, without specifying which has been used where, and there is no way to find out.
Is there a way to get something like an average out of those data points, or is too much crucial information missing?
EDIT: This question should be deleted. I realized I misread the data in question: values with a standard deviation are means, values without are median. Thank you for your help, and sorry for bothering you.