8.1 Sampling designs. See ../StatPrimer/independ-odd.htm |
[3 pts]
8.2 Sampling designs, 2.
(A) Needle stick injuries. Independent samples
(B) Public health laboratory. Single sample.
(C) Public health laboratory, 2. Paired samples.
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8.5 Large t statistic. See ../StatPrimer/independ-odd.htm
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8.7 Bone density in newborns. See ../StatPrimer/independ-odd.htm |
8.8 Joggers.
-
df1 = 25-1 = 24,
df2 = 26-1 = 25, df = 24 + 25 = 49
-
Use df = 50 as closest approximation and t50,.975 = 2.01
- s2pooled = [(24)(4.82) + (25)(5.12)] /
49 = 24.60
- sexbar1-xbar2 = [24.60 � (1/25 + 1/26)] = 1.389
- 95% CI for �1 - �2 = (47.5 - 37.5) �
(2.01)(1.389) = 10.0 �
2.8 = (7.2, 12.8)
- Interpretation: We are 95% confident that the population mean difference �1 - �2
lies between 7.2 and 12.8. (The source http://www.thefitnessexpert.com/cardio_coach.html
suggests that this is quite a meaningful improvement in metabolism.)
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8.9 Cytomegalovirus. See ../StatPrimer/independ-odd.htm |
[7 pts]
8.10 Hemodialysis and anxiety. State-Trait Anxiety Inventory Score
-
H0: �1 = �2
vs. H1: �1 not = �2
-
df1 = 38 - 1 = 37,
df2 = 23 - 1 = 22, df = 37 + 22 =
59
- s2pooled = 96.277
- sexbar1-xbar2 = 2.5922
-
tstat = (33.42 - 39.71) / 2.5922 =
-2.43 with 59 df (use either df = 50 or df = 100 as closest
approximation)
- Two sided p value: .01 < p < .02
- The difference is significant. There does appear to be some
benefit associated with the progressive relaxation tapes.
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SS.1 Vegetarians and non-vegetarians. See ../StatPrimer/independ-odd.htm |
SS.2. Allopathic and holistic medicine.Use
n = 116 per group. |