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Estimating Methods, Variability, and Sampling for Drop-Test Data
The following cups (table 8) and lids (table 9) were used and their weight recorded.
| Weight range (grams) |
Average (grams) |
Total cups |
|---|---|---|
| 26.85 to 26.95 | 26.90 | 5,000 |
| 26.75 to 26.85 | 26.80 | 4,000 |
| 26.65 to 26.75 | 26.70 | 3,000 |
| Weight range (grams) |
Average (grams) |
Total cups |
|---|---|---|
| 16.45 to 16.55 | 16.50 | 2,500 |
| 16.35 to 16.45 | 16.40 | 8,500 |
Average cup weight = [(26.9*5) + (26.8*4) + (26.7*3)]/12 = 26.816667 grams
Standard deviation = 0.07993 grams. Variance = 0.0063888049 grams
Average lid weight = [(16.4*8.5) + (16.5*2.5)]/11 = 16.422727 grams
Standard deviation = 0.04191 grams. Variance = 0.0017564481 grams
Tare (average weight of cup and lid) = 43.23939 grams
Combined standard deviation:
The lowest possible cup and lid weight was 43.00 grams and the highest was 43.50. If a cup with retardant in it weighed less than 43.23939 grams, the computer program automatically switched to a tare weight of 43.00 to avoid negative gpc.
At a 99-percent confidence level (CI), the margin of error for the tare weight of
43.2393 grams is ± 0.23249
(2.576*0.09025 = 0.23249)
At a 95 percent CI, the margin of error for the tare weight is ± 0.17689 grams.
(1.960*0.09025 = 0.17689 grams)
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