Number of steps (in thousands) taken by 1 persons in a day are: 12, 7 , 15, 10, 17, 19, 25 The Quartile deviation is

Arrangement of the given data in ascending order of magnitude is: 7, I0, 12, 15, 17, 19,25  Here, Q1= size of n+14th item = size of 2 nd item =10Q3= size of 3(n+1)4th item = size of 6 th item =19 Then Q.D. =Q3−Q12=19−102=4.5