Q4 of 145 Page 370

Find the mean, using direct method:





















Class



0 - 10



10 - 20



20 - 30



30 - 40



40 - 50



50 - 60



Frequency



7



5



6



12



8



2


For equal class intervals, we will solve by finding mid points of these classes using direct method.



















































CLASS



MID - POINT(xi)



FREQUENCY(fi)



fixi



0 - 10



5



7



35



10 - 20



15



5



75



20 - 30



25



6



150



30 - 40



35



12



420



40 - 50



45



8



360



50 - 60



55



2



110



TOTAL




40



1150



We have got


Σfi = 40 & Σfixi = 1150


∵ mean is given by



⇒


⇒


Thus, mean is 28.75


More from this chapter

All 145 →
2

If the mean of 25 observations is 27 and each observation is decreased by 7, what will be the new mean?

 3

Compute the mean of the following data:

















Class



1 - 3



3 - 5



5 - 7



7 - 9



Frequency



12



22



27



19


 5

Calculate the mean of the following data, using direct method:



















Class



25 - 35



35 - 45



45 - 55



55 - 65



65 - 75



Frequency



6



10



8



12



4


 6

Compute the mean of the following data, using direct method:



















Class



0 - 100



100 - 200



200 - 300



300 - 400



400 - 500



Frequency



6



9



15



12



8