Question

Section II
17. Class X students appeared for a test and the marks obtained are formulated in a table as follows (out of 100).
MARKS
0-20
8
20-40
12
40-60
20
60-80
30
80-100
10
NO. OF STUDENTS
Attempt any 4 sub-parts.
(i)
How many students secured less than 60 marks?
(a)20 (b)32 (c) 40 (d) 70
What is the upper limit of the modal class?
(a)20 (b)40 (c) 60
(d) 80
(d) 80
(iii) What is the lower limit of the median class?
(a)20 (b)40 (c) 60
(iv) Cummulative frequency table is constructed to determine
(a)Mean
(b)Median
(c) Mode
(d) All of these
(v) The emperical relationship between mean, median and mode is
(a) 3 Median-2 Mean = Mode
(b) 3 Median - 2Mode = Mean
(c) 2 Median - 3 Mean= Mode
(d) Median + 2Mean = 3 Mode​

Answer 1

Answer:

Marksobtained No.ofstudents

(f) Cumulativefrequency

0−20 4 4

20−40 6 10

40−60 25 35

60−80 10 45

80−100 5 50

⇒ Here, N=50, then

2

N

=

2

50

=25

We can see, 25 is nearest to cumulative frequency 35 which has class interval 40−60

∴ Median class =40−60.

⇒ In frequency table we can see class 40−60 has highest frequency 25.

∴ Modal class =40−60

Answer 2

Answer:

Answer:

Marks                  : 0-10    10-20    20-30    30-40    40-50    50-60  

No. of Students :   8          12           20         30           10          10

Cumulative frequency :   8     20          40         70           80         90

A)d) 70

Total number of students (n) = 90

n/2 = 90/2 = 45

As 45 < 70

So, 30 - 40 is the median class.

B)Lower limit of the median class (l) = 30

C)(b)median

D)(a) 3 Median-2 Mean = Mode