13. Find the mean, mode and median for the following data:
according to given observation:
|class interval (CI)||frequency f||cumulative frequency||midpoint of CI (x)||fx|
to find the median : we will apply the formula ;
75/ 2 = 37.5.
this lies in the interval 30-40.
i = size of the class interval
L = lower limit of the CI which includes the median score.
F = cumulative frequency up to median CI
f = frequency in the class interval that contains the median.
therefore L = 30 ; F = 28 ; f = 20 ; i =10
thus median =
L = lower class boundary of modal class
the frequency of the modal class
previous frequency of the modal class
the next frequency of the modal class
i = size of the modal class
modal class is the class with maximum frequency
from the observation: maximum frequency = 20.
modal class = 30-40
L = 30 ; 20 ; 15 and 14 ; i = 10
= 30 + (5/11)
= 30 + 0.4545
hope this helps you.