anyone know what a quartile class is? to find q1 i need to use the lower boundary of the first quartile class, but i don't even know what that is.

Question

anonymous · Answer

The values that divide the data set into 4 equal parts after it has been arranged in ascending orden are called quartiles.

anonymous · Answer

Q1 , the lowest quartile is known as the lower quartile, or first quartile. The lowest 25% of the data being found below the first quartile value. It is the same as P25.

anonymous · Answer

Do u wanna know what rest of the quartiles are?

realsiege · Answer

sorry, i still don't get it. so for example if my chart consists of:
0-10
11–20
21-30
31-40
41-50
51-60
61-70
71-80
81-90
91-100

what's my Q1?

anonymous · Answer

21-30

anonymous · Answer

This falls in 25% category

imqwerty · Answer

i hate statistics!    ┻━┻ ︵ヽ(`Д´)ﾉ︵ ┻━┻

realsiege · Answer

(i wrote this for archive so i can check it again) ahh i finally know what it is

group     freq    cumulative freq
1-10        6               6
11–20      6              12
21-30      9              21
31-40     21             42
41-50     20             62    Q1
51-60     16             78
61-70     25            103
71-80     17            120
81-90     26            146   Q3
91-100   45            191
total       191     

so multiply 1/4 with n (total frequency) [if it's odd: total freq + 1] 
1/4*191+1 = 48

somewhere up in the data the 48th data is in there
it's group 41-50

and Q3 is in group 81-90 because the 144th data is in there

i feel so happy rn