Does polyester decay? How quickly do synthetic fabrics such as polyester decay in landfills? A researcher buried polyester strips in the soil for different lengths of time, then dug up the strips and measured the force required to break them. Breaking strength is easy to measure and is a good indicator of decay; lower strength means the fabric has decayed.

Part of the study buried 20 polyester strips in well-drained soil in the summer.

Five of the strips, chosen at random, were dug up after each of 2 weeks, 4 weeks, and 8 weeks. Here are the breaking strengths in pounds:18 2 weeks 118 126 126 120 129 4 weeks 130 120 114 126 128 8 weeks 122 136 128 146 140 The investigator conjectured that buried polyester loses strength over time. Do the data support this conjecture? Follow the four-step process in data analysis and ANOVA. Be sure to check the conditions for ANOVA.