9th Class
Mathematics
Sample Paper
Maths Olympiad Model Test Paper-3
question_answer
If \[{{x}_{i}}'s\] are the midpoints of the class intervals of a grouped data, \[{{f}_{i}}'s\] are the corresponding frequencies and \[\overline{x}\] is the mean, then what is \[\sum\limits_{{}}^{{}}{{{f}_{i}}({{x}_{i}}-\overline{x})}\] equal to?