Answer:
1.44
Explanation:
No. of warp coils manufactured in one group = 36
defect rate = 4%
That is 4 out of every 100 warp coil is defective
No. of defective warp coil in one group = 4% of warp coil in one group
= 4% of 36 =4/100 *36
= 1.44
Thus, there are 1.44 defective coil in each group.
Since, mean number is average number of defect.
So if each group has 1.44 defective coils then mean for all the group will remain same i.e 1.44