Q5 of 141 Page 7



















Class interval:



0-6



6-12



12-18



18-24



24-30



Frequency:



6



8



10



9



7


Let A assumed mean be 15.



























































Class interval



Mid value (xi)



di = xi - 15



ui =



fi



fiui



0 – 6



3



-12



-2



6



-12



6 – 12



9



-6



-1



8



-8



12 – 18



15



0



0



10



0



18 – 24



21



6



1



9



9



24 – 30



27



12



2



7



14







N = 40



∑fiui = 3



A = 15, h = 6


Mean = A + h *


= 15 + 6 *


= 15 + 0.45


= 15.45


More from this chapter

All 141 →
3

Consider the following distribution of daily wages of 50 workers of a factory.



















Daily wages (in Rs):



100-120



120-140



140-160



160-180



180-200



Numbers of workers:



12



14



8



6



10



Find the mean daily wages of the workers of the factory by using an appropriate method.

 4

Thirty women were examined in a hospital by a doctor and the number of heart beats per minute recorded and summarized as follows. Find the mean heart beats per minute for these women, choosing a suitable method.























Number of heart beats per minute:



65-68



68-71



71-74



74-77



77-80



80-83



83-86



Number of women:



2



4



3



8



7



4



2



Find the mean of each of the following frequency distributions: (5-14)

 6





















Class interval:



50-70



70-90



90-110



110-130



130-150



150-170



Frequency:



18



12



13



27



8



22


 7



















Class interval:



0-8



8-16



16-24



24-32



32-40



Frequency:



6



7



10



8



9