National Partamiento Co.
Months in
Service
Number
Installed
Number
Failed
Number Not
Failed
Cumulative
Failures
Month x
Failures
Months in
Service
Monthly Failure
Rate
124440 124439 1 1 1 0.00004092 0.00004092 Regression on number of units failed by month
224439 324436 4 6 2 0.00012275 0.00016367
324436 624430 10 18 3 0.00024554 0.00040921
424430 10 24420 20 40 4 0.00040933 0.00081854 SUMMARY OUTPUT
524420 11 24409 31 55 5 0.00045045 0.00126899
df SS MS F Significance F
Regression 1 1201.47028 1201.47028 359.2227411 3.62759E-09
Average failure rate (lambda) = 0.000680109 Residual 10 33.4463869 3.344638695
Total 11 1234.91667
Months in
Service
Number
Installed
Number
Failed
Number Not
Failed
Cumulative
Failures
Monthly
Failure Rate
14 24206 38 24168 272 0.00156986 Intercept -2.257575758 1.12557034 -2.005717166 0.072692006 -4.765502769 0.2504 -4.765502769 0.250351254
15 24168 41 24127 313 0.00169646 Months in Service 2.898601399 0.15293489 18.95317232 3.62759E-09 2.55784122 3.2394 2.55784122 3.239361578
16 24127 44 24083 357 0.00182368
17 24083 47 24036 404 0.00195158
18 24036 50 23986 454 0.00208021
19 23986 53 23933 507 0.00220962 RESIDUAL OUTPUT
20 23933 56 23877 563 0.00233987
21 23877 59 23818 622 0.00247100 Observation Predicted Number Failed Residuals
22 23818 62 23756 684 0.00260307 1 0.641025641 0.35897436
23 23756 64 23692 748 0.00269406 2 3.53962704 -0.53962704
24 23692 67 23625 815 0.00282796 3 6.438228438 -0.43822844
25 23625 70 23555 885 0.00296296 4 9.336829837 0.66317016
26 23555 73 23482 958 0.00309913 5 12.23543124 -1.23543124
27 23482 76 23406 1034 0.00323652 6 15.13403263 -1.13403263
Percent failure over 36 months =
7.56
20
25
30
35
Months in Service Line Fit Plot
724395 20 24375 65 140 7 0.00081984 0.00266239 Multiple R 0.986365083
824375 21 24354 86 168 8 0.00086154 0.00352393 R Square 0.972916078
924354 23 24331 109 207 9 0.00094440 0.00446833 Adjusted R Square 0.970207686