Question

find mean class interval 5-10,10-15,15-20,20-25,25-30,30-35 , frequensy 2,3,6,7,2,5

Answer 1

Mean=22.5-6/25×5

=22.5-6/5

=22.5-1.2

=21.3

Answer 2

Answer:

21.3

Step-by-step explanation:

We need to get the midpoint of each of the class intervals.

The midpoint (x) = (Lower limit + upper limit)/2

1: (4.5 + 10.5)/2 = 7.5  ; fx =7.5 × 2 = 15

2: (9.5 + 15.5) / 2 = 12.5   ; fx = 12.5 × 3 = 37.5

3: (15.5 + 20.5)/2 = 17.5  ; fx = 17.5 × 6 = 105

4: (19.5 + 25.5)/2 = 22.5  ; fx = 22.5 × 7 = 157.5

5: (24.5 + 30.5)/2 = 27.5  ; fx = 27.5 ×2 = 55

6: (29.5 + 35.5)/2 = 32.5  ; fx = 32.5 × 5 = 162.5

∑f = 2 + 3 + 6 + 7 + 2 + 5 = 25

∑fx = 15 + 37.5 + 105 + 157.5 + 55 + 162.5 = 532.5

Mean = ∑fx/ ∑f

= 532.5/25 = 21.3

To answer this question well we need the x (mid point column) , The fx ( frequency × midpoint) column and the frequency (f) column.