Question

8. Find the mean:
Marks
less than 20 less than 40 less than 60 less than 80 less than 100
No. of Students 4 10 28 36 50​

Answer 1

Answer:

mean =sum of all observation/no.of observation

4+10+28+36+58/5

136/5

27.2 .

hope it helps you

Answer 2

ANSWER:

CLASS INTERVAL FREQUENCY Xi FiXi LESS THAN 20 4 10 40 LESS THAN 40 10 30 300 LESS THAN 60 28 50 1400

LESS THAN 80 36 70 2520

LESS THAN 100 50 90 4500

Sum of FiXi = 8760

N = 128

MEAN = 8760/ 128

= 68.4

REQUIRED MEAN = 68.4