Use the following data to construct p-chart and np-chart. The number of nonconforming switches in samples of size 180 is given below:

Sample number	No. of defectives
1	8
2	1
3	3
4	0
5	2
6	4
7	0
8	1
9	10
10	6
11	6
12	0
13	4
14	0
15	3
16	1
17	15
18	2
19	3
20	0

Questions:

1. Construct 2 and 3 control limits
2. Find the number of points falling outside 2 control limits
3. Find the number of points falling outside 3 control limits
4. Is the process under control? If not, revise the control limits till the process becomes control.
5. What is the probability of detecting atleast one defective? Comment on the sample size?
6. If the process average shifts to UCL how many samples are needed to detect this shift?