CBSE Class 11-science Answered

assumed mean is to be calculated which have large numerical data,to reduce calculation we assume a mean and then write a new table of data by substracting this assumed mean from each data so that data become small,generally middle data is considered as assumed mean.now data becomes small so calculation is easy.in the end we add mean to the answer and get final answer,in question which are not having data it is not necessary to consider assumed mean.