The process engineer in a textile company suspects that there might be significant variations in strength of a fabric between looms in addition to the usual variation within samples of fabric from the same loom. Four looms are selected at random and four strength determinations are made from fabric on each loom. The data is shown below.
Source: Montgomery, D.C. (2001). The Design and Analysis of Experiments. John Wiley & Sons: New York.
Table 17: Strength Data
| Looms | Observations |
|---|---|
| 1 | 98 97 99 96 |
| 2 | 91 90 93 92 |
| 3 | 96 95 97 95 |
| 4 | 95 96 99 98 |
Questions:
Keywords: One-factor model, random effects, variance components