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286 CHAPTER 7 HYPOTHESIS TESTING
Treatment Mean Standard Error of Mean
Etanercept 5.56 0.84
Etanercept plus methotrexate 4.40 0.57
21. Miyazaki et al. (A-36) examined the recurrence-free rates of stripping with varicectomy and stripping
with sclerotherapy for the treatment of primary varicose veins. The varicectomy group consisted
of 122 limbs for which the procedure was done, and the sclerotherapy group consisted of 98
limbs for which that procedure was done. After 3 years, 115 limbs of the varicectomy group and 87
limbs of the sclerotherapy group were recurrence-free. Is this sufficient evidence for us to conclude
there is no difference, in general, in the recurrence-free rate between the two procedures for treating
varicose veins Let a = .05.
22. Recall the study, reported in Exercise 7.8.1, in which Dora et al. (A-37) investigated spinal
canal dimensions in 30 subjects symptomatic with disc herniation selected for a discectomy
and 45 asymptomatic individuals (control group). One of the areas of interest was determining
if there is a difference between the two groups in the spinal canal cross-sectional area (cm 2 )
between vertebrae L5/S1. The data in the following table are simulated to be consistent with
the results reported in the paper. Do these simulated data provide evidence for us to conclude
that a difference in the spinal canal cross-sectional area exists between a population of subjects
with disc herniations and a population of those who do not have disc herniations Let
a = .05.
Herniated Disc Group
Control Group
2.62 2.57 1.98 3.21 3.59 3.72 4.30 2.87 3.87 2.73 5.28
1.60 1.80 3.91 2.56 1.53 1.33 2.36 3.67 1.64 3.54 3.63
2.39 2.67 3.53 2.26 2.82 4.26 3.08 3.32 4.00 2.76 3.58
2.05 1.19 3.01 2.39 3.61 3.11 3.94 4.39 3.73 2.22 2.73
2.09 3.79 2.45 2.55 2.10 5.02 3.62 3.02 3.15 3.57 2.37
2.28 2.33 2.81 3.70 2.61 5.42 3.35 2.62 3.72 4.37 5.28
4.97 2.58 2.25 3.12 3.43
3.95 2.98 4.11 3.08 2.22
Source: Simulated data.
23. Iannelo et al. (A-38) investigated differences between triglyceride levels in healthy obese (control)
subjects and obese subjects with chronic active B or C hepatitis. Triglyceride levels of
208 obese controls had a mean value of 1.81 with a standard error of the mean of .07 mmol/L.
The 19 obese hepatitis subjects had a mean of .71 with a standard error of the mean of .05. Is
this sufficient evidence for us to conclude that, in general, a difference exists in average triglyceride
levels between obese healthy subjects and obese subjects with hepatitis B or C Let
a = .01.
24. Kindergarten students were the participants in a study conducted by Susan Bazyk et al. (A-39).
The researchers studied the fine motor skills of 37 children receiving occupational therapy. They
used an index of fine motor skills that measured hand use, eye–hand coordination, and manual