Calcilation `Q_(1),Q_(3),D_(6)and P_(85)` from the following data :
`{:("Size",10,11,12,13,14,15,16,17,18),("Frequency",3,4,5,12,10,7,5,2,1):}`

Explanation

`Q_(1)`= Size of `((N+1)/(4))` th item = Size of `((49+1)/(4))` th item
= Size of 12.5th item =13
`Q_(3)` = Size of `3((N+1)/(4))` th item = Size of `((49+1)/(4))` th item
= Size of 37.5th item =15
`D_(6)` = Size of `6((N+1)/(10))` th item = Size of `6((49+1)/(10))` th item
= Size of 30th item = 14
`P_(85)` `85((N+1)/(100))` th item = Size of `85((49+1)/(100))`th item
= size of 42 .5th item =16
Thus, `Q_(1)=13,Q_(2)=15,D_(6)=14,P_(85)=16`.