Strength of cotton yarn

An experiment was done with the objects of estimating:

the difference in mean strength of two worsted yarns produced by slightly different processes, and

the variation of strength between and within bobbins for yarns of this type.

For each yarn a considerable number of bobbins were produced and six bobbins selected at random. From each of these, four short lengths were chosen at random for strength testing. The breaking loads are given in Table Q.1.