Day |
Obs (ppb) |
Day |
Obs (ppb) |
Day |
Obs (ppb) |
Day |
Obs (ppb) |
Day |
Obs (ppb) |
0 |
1.05 |
91 |
1.13 |
147 |
0.83 |
212 |
1.03 |
290 |
1.04 |
1 |
0.70 |
101 |
1.64 |
149 |
0.88 |
218 |
0.90 |
294 |
0.85 |
3 |
0.42 |
104 |
0.79 |
154 |
0.89 |
220 |
0.86 |
296 |
0.59 |
6 |
0.95 |
106 |
0.66 |
156 |
0.72 |
237 |
1.05 |
300 |
0.83 |
7 |
0.55 |
112 |
0.88 |
161 |
1.18 |
251 |
0.79 |
302 |
0.67 |
30 |
0.68 |
113 |
0.79 |
167 |
0.75 |
259 |
0.94 |
304 |
0.66 |
70 |
0.83 |
115 |
1.07 |
175 |
0.76 |
262 |
0.77 |
308 |
1.04 |
72 |
0.97 |
119 |
0.60 |
182 |
0.93 |
277 |
0.85 |
311 |
0.86 |
76 |
0.60 |
125 |
0.80 |
185 |
0.72 |
282 |
0.72 |
317 |
0.88 |
80 |
0.87 |
128 |
0.81 |
189 |
0.87 |
286 |
0.68 |
321 |
0.67 |
84 |
1.03 |
134 |
0.84 |
199 |
0.85 |
288 |
0.86 |
323 |
0.68 |
Here sum of all the observations = 9835.21
Number of observations= 110
Therefore, mean = sum of the observations / Number of observations
= 9835.21/110
=89.41
Variance = where X= observation, n= number of observations
Therefore, Sample Variance = = 12563.25
Standard Deviation (SD) = =112.09
Lower Control Limit (LCL)=mean -( 3 *SD) = 89.41 - (3*112.09) = - 246.86
Upper Control Limit (UCL) =mean + (3*SD) = 89.41 + (3*112.09) = 425.68
Control Chart is given below
Here we see that all the observations are within the control limit.
[ To find
= (0-89.41)^2 +(1-89.41)^2 +.......+(0.68-89.41)^2
=1369393.77 ]
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