Question

Find the mean and standard deviation:
С.І.
5-15
15-25
25-35
35-45
45-55

frequency
8
12
15
6
9​

Answer 1

Step-by-step explanation:

c.I. f. x d. u

5-15. 8. 10. 0. 0

15-25. 12. 20. 10. 1

25-35. 15. 30. 20. 2

35-45. 6. 40. 30. 3

45-55. 9 50. 40. 4

50. 10

step deviation = a + £fiui/£f × h

= 10 + 10/50 × 10

= 10 + 2

= 12