Experts can you please tell me how to do this question ?
Dear Student,
| For Brand A |
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| Life (in hours) | No. of bulbs | M | A = 125 |
| d'2 | fd' | fd'2 | |
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| f | x | X – A = d |
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| 0 – 50 | 15 | 25 | – 100 | – 2 | 4 | – 30 | 60 | |
| 50 – 100 | 20 | 75 | – 50 | – 1 | 1 | – 20 | 20 | |
| 100 – 150 | 18 | 125 | 0 | 0 | 0 | 0 | 0 | |
| 150 – 200 | 25 | 175 | 50 | 1 | 1 | 25 | 25 | |
| 200 – 250 | 22 | 225 | 100 | 2 | 4 | 44 | 88 | |
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| For Brand B
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| Life (in hrs) | No. of bulbs (f) | Mid value m | A = 125 |
| d'2 | fd' | fd'2 | |
| 0 – 50 | 2 | 25 | – 100 | – 2 | 4 | – 4 | 8 | |
| 50 – 100 | 8 | 75 | – 50 | – 1 | 1 | – 8 | 8 | |
| 100 – 150 | 60 | 125 | 0 | 0 | 0 | 0 | 0 | |
| 150 – 200 | 25 | 175 | 50 | 1 | 1 | 25 | 25 | |
| 200 – 250 | 5 | 225 | 100 | 2 | 4 | 10 | 20 | |
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(i) The average life of bulb of Brand B has comparatively higher life than the bulb of Brand A.
(ii) The bulbs of Brand B is more dependable as CV of Brand B is lesser than CV of Brand A.
Regards