Question

The weight of 40 students are given below . Construct a frequency polygon for the given data .
Weight (In kg.) : 30–35 35–40 40–45 45–50 50–55 55–60,
No.of Students : 10 07 16 04 01 02.
​

Answer 1

Step-by-step explanation:

Weight (in kg) Number of students

(Frequency) Cumulative

Frequency

40 - 45 2 2

45 - 50 3 5

50 - 55 8 13

55 - 60 6 19

60 - 65 6 25

65 - 70 3 28

70 - 75 2 30 =n

We have, n=30

2

n

=15

The cumulative frequency just greater than

2

n

is 19 and the corresponding class is 55–60.

Thus, 55–60 is the median class such that

2

n

=15,l=55,f=6,cf=13 , and h=5

Substituting these values in the formula

Median, M=l+

⎝

⎛

f

2

n

−cf

⎠

⎞

×h

M=55+(

6

15−13

)×5

M=55+

6

2

×5=55+1.67=56.67

Hence, the median weight =56.67 kg .