What is the third quartile of this data set 21,24,25,28,29,35,37,43,44

40

Step-by-step explanation:

The data is

21,24,25,28,29,35,37,43,44

To find the third quartile we have to arrange the data in increasing order

so the data in increasing order is

21,24,25,28,29,35,37,43,44

total number of values = 9

Median value = (n + 1 )/ 2

                       =(9+1)/2

                       =5th value

so the median is  29

Lower half of the data is the values before the median and upper half of the data is values after the median

so lower half = {21,24,25,28}

Upper half = {35,37,43,44}

so to find the third quartile we will use the upper half of the values

Third quartile means that the median of the values of upper half of the data

As the total No of value in upper half is 4 which is an even no

we will take the middle values of the upper half and take their mean

so

Third Quartile =

                        =

                        =40

so the value of third quartile is 40