Amount paid ₹ |
No. of customers f |
Cumulative frequency cf |
0-50 |
25 |
25 |
50- 100 |
40 |
65 |
100-150 |
80 |
145 |
150-200 |
30 |
175 |
200 – 250 |
25 |
200 |
Total |
n = 200 |
- |
First Quartile:
Q1 Class = Class that Includes \(\left(\frac{n}{4}\right)\)th observation
= Class that includes \(\left(\frac{200}{4}\right)\) = 50th observation
Referring to column cf
Q1 class = 50 – 100
Now, Q1 = L + \(\frac{\left(\frac{n}{4}\right)-c f}{f}\) × c
Putting L = 50: \(\left(\frac{n}{4}\right)\) = 50: cf = 25: f = 40 and c = 50 In the formula,
Third Quartile:
Q3 Class = Class that Includes 3 \(\left(\frac{n}{4}\right)\)th observation
= Class that Includes 3 (50)th = 150th observation
Referring to column cf. Q3 class = 150 – 200
Now. Q3 = L + \(\frac{3\left(\frac{n}{4}\right)-c f}{f}\) × c
Putting L = 150: 3 \(\left(\frac{n}{4}\right)\) = 150: cf = 145; f = 30 and c = 50 in the formula.