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<td> <div align="center">12</div></td> | <td> <div align="center">12</div></td> | ||
The results are: | |||
Difference = p (1) - p (2) | |||
Estimate for difference: 0.170035 | |||
95% CI for difference: (0.0346494, 0.305420) | |||
Test for difference = 0 (vs not = 0): Z = 2.37 P-Value = 0.018 | |||
Fisher's exact test: P-Value = 0.026 | |||
Discussion | |||
1. Why is the Fisher exact test P-Value (0.026) to be preferred to the other P-Value mentioned (0.018)? | |||
2. The Wall Street Journal mentioned several caveats “making it difficult to determine the underlying reasons for the after-hours patients’ poor outcomes.” List a few practical significance hedges to the statistically significant result. | |||
<td> <div align="center">70</div></td> | |||
<td> <div align="center">.1714</div></td> | |||
</tr> | |||
</table> | |||
Revision as of 14:04, 13 September 2009
Breaking News
The Wall Street Journal of September 8, 2009 reports on a study in the Journal of Bone and Joint Surgery: “The researchers compared the outcomes of patients who underwent surgery between 6 a.m. and 4 p.m. for fractures of the femur or tibia to those who had comparable surgeries for similar fractures outside those normal hours.”
The results are:
Difference = p (1) - p (2) Estimate for difference: 0.170035 95% CI for difference: (0.0346494, 0.305420) Test for difference = 0 (vs not = 0): Z = 2.37 P-Value = 0.018
Fisher's exact test: P-Value = 0.026
Discussion
1. Why is the Fisher exact test P-Value (0.026) to be preferred to the other P-Value mentioned (0.018)?
2. The Wall Street Journal mentioned several caveats “making it difficult to determine the underlying reasons for the after-hours patients’ poor outcomes.” List a few practical significance hedges to the statistically significant result.
| Sample | Reoperations Needed |
Sample Size |
Sample Proportion |
|
| Outside Normal Hours | 28 |
82 |
.. | |
| Within Normal Hours | 12 |
70 |
.1714 |