Statistics

Find the Mean Deviation about median for the following data :
























Class



0  - 10



10 - 20



20 - 30



30 - 40



40 - 50



50 - 60



60 - 70



70 - 80



frequency



5



8



7



12



28



20



10



10



Find the mean $$S.D$$ of $$1,2,3,4,5,6$$. 
Find the median and mode of the following data.
$$28$$ , $$15$$ , $$40$$ , $$25$$ , $$16$$ , $$28$$ , $$32$$ , $$36$$ , $$42$$ , $$16$$ , $$19$$ , $$23$$
What is the mean value of below numbers?
$$2,5,6,8,7,5,4,3,5,2,2,$$
The sum of squares of deviations for $$10$$ observations taken from mean $$50$$ is $$250 $$. Then Co-efficient of variation is