In chapter 14 how do we come to know that which method of mean we have to use if it is not given

In chapter 14 how do we come to know that which method of mean we have

1.	In chapter 14 how do we come to know that which method of mean we have to use if it is not given
Answer» when the frequency and the class intervals are small then the direct mean method is used.......if the class intervals are large and the height of class interval is same then the step deviation is used......and if the class intervals are large but height of the class interval is different then the assumed mean method is used where no height is required.......and if we have to find the value of \'x or y\' then always use direct method......HOPE IT WILL HELP YOU!! U cn use any..if it is not given