7.118 Durable press and breaking strength.
“Durable press’’ cotton fabrics are treated to improve their recovery from wrinkles after washing. Unfortunately, the treatment also reduces the strength of the fabric. A study compared the breaking strength of fabric treated by two commercial durable press processes. Five specimens of the same fabric were assigned at random to each process. Here are the data, in pounds of pull needed to tear the fabric:42
brkstr
| Permafresh 55 | 29.9 | 30.7 | 30.0 | 29.5 | 27.6 |
| Hylite LF | 28.8 | 23.9 | 27.0 | 22.1 | 24.2 |
Is there good evidence that the two processes result in different mean breaking strengths?