98. Long-term exposure of textile workers to cotton dust released during processing can result in substantial health problems, so textile researchers have been investigating methods that will result in reduced risks while preserving important fabric properties.

The accompanying data on roving cohesion strength (kN  m/kg) for specimens produced at ve different twist multiples is from the article Heat Treatment of Cotton: Effect on Endotoxin Content, Fiber and Yarn Properties, and Processability (Textile Res. J., 1996: 727—738).

Twist multiple 1.054 1.141 1.245 1.370 1.481 Control strength .45 .60 .61 .73 .69 Heated strength .51 .59 .63 .73 .74 The authors of the cited article stated that strength for heated specimens appeared to be slightly higher on average than for the control specimens. Is the difference statistically signi cant? State and test the relevant hypotheses using a.05 by calculating the P-value.