Power is the probability that a study will reject the null hypothesis. difference between the null and alternative hypotheses. level of significance, and the null vs. alternative difference. a numeric example of power and sample size estimation for the one-sample case.
During the procedure the patient is unconscious and unaware of the need to urinate. After the procedure, however, it may not be safe for the patient to walk. They may be too sick to take care of their own bathroom needs or their surgeon may feel that a catheter is best for their particular recovery.
Once the decision has been made to use an indwelling urinary catheter, efforts should be made to minimize problems. The catheter should be inserted using sterile technique (Table 3) . 5 Once inserted, the catheter should be anchored to prevent urethral traction.