Determining decay rates for styrofoam packaging in landfills. A researcher buried styrofoam cups in the soil for different lengths of time, then dug up the strips and measured the force required to tear them apart. Breaking strength is a good measure and is a good indicator of decay. Lower strength means the styrofoam has decayed more. For one part of the study, the cups were randomly assigned to two groups: 5 of them were buried for 4 weeks and the other 5 were buried for 16 weeks. Hear are the breaking strengths in pounds. At significance level of 0.05 GROUP 1: 75 84 837887 GROUP 2: 8262 74 90 74