10.163 [EX10-163] A research project was undertaken to evaluate the amount of force needed to elicit a designated response on equipment made from two distinct designs: the existing design and an improved design. The expectation was that new design equipment would require less force than the current equipment. Fifty units of each design were tested and the required force recorded. A lower force level and reduced variability are both considered desirable.

Control or Existing Test or New Design 0.003562 0.002477 0.005216 0.002725 ••• Remainder of data on Student’s Suite CD-ROM

a. Describe both sets of data using means, standard deviations, and histograms.

b. Check the assumptions for comparing the variances and means of two independent samples.
Describe your findings.

c. Will one- or two-tailed tests be appropriate for testing the expectations for the new design?
Why?

d. Is there significant evidence to show that the new design has reduced the variability in the required force? Use   0.05.

e. Is there significant evidence to show that the new design has reduced the mean amount of force? Use   0.05.

f. Did the new design live up to expectations?
Explain.