1. Teaching associates who give classes in computer labs at the Ohio State University are required to write on white boa

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1 Teaching Associates Who Give Classes In Computer Labs At The Ohio State University Are Required To Write On White Boa 1 (270.56 KiB) Viewed 21 times

1. Teaching associates who give classes in computer labs at the Ohio State University are required to write on white boards with " dry markers" rather than on chalk boards with chalk. The ink from these dry markers can stain rather badly, and an experiment was planned by M. Chambers, Y.- W. Chen, E. Kurali and R. Vengurlekar in 1996 to determine which type of cloth (factor A, 1 = cotton/polyester, 2 = rayon, 3 = polyester) was most difficult to clean, and whether a detergent plus stain remover was better than a detergent without stain remover (factor B, levels 1, 2) for washing out such a stain. Pieces of cloth were to be stained with 0.1 ml of dry marker ink and allowed to air dry for 24 hours. The cloth pieces were then to be washed in a random order in the detergent to which they were allocated. The stain remaining on a piece of cloth after washing and drying was to be compared with a 19 point scale and scored accordingly, where 1 = black and 19= white. (d) Calculate the number of observations that you would need to take on each treatment combination in order to try to ensure that the lengths of confidence intervals for pairwise differences in the effects of the levels of each of the factors were no more than 2 points (on the 19-point scale).