stat 1213 / Final / 1998 December 8 / page 3
PART III   [25]
For each of the stories on the next page select an appropriate method from the list shown. (The question addressed by the experiment is sometimes implied rather than stated.)
Paired Test (Sign or Paired T-Test)
Unpaired Test (Mann-Whitney or Unpaired T-Test)
Chi Square Test

A)   Will a paper airplane fly farther if you add a paper clip for weight? Every student in the class makes a paper airplane and throws it at the teacher, once with clip, once without clip. (In random order, of course.)

B)   Forty subjects taste on glass of soft drink C and one of drink D in a blindfold test and express a preference. Of course C and D are presented in random order.

C)   To test the effect of Vitamin C in preventing colds, ten of twenty patients are randomly selected to receive vitamin C; the other ten receive placebo capsules. The number of Colds during 12 months --
4 0 3 4 4 3 4 3 2 6
7 8 4 6 6 4 5 4 5 7

D)   A stress analysis was conducted to compare expoxy-repaired truss joints in damaged timber structures made from two species of wood, namely Southern Pine and Ponderosa Pine. Repaired joints from forty (40) structures made from Southern Pine and forty made from Ponderosa Pine were selected for study. The mean shear stress of each joint, in pounds per square inch, was determined.

                    Browsed  Heavily Lightly
   Deforested by Lumbering     15      15
   Deforested by Insectects    11      19 
Do moose browse more heavily in areas deforested by insects? In a large forest, sixty (60) study plots are randomly selected in each type of area. The plots are rated as lightly or heavily browsed.
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