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.
Selecting a Catheter. 1  The Foley catheter is used in almost all cases when an indwelling urinary catheter is required. 2  For routine, short-term catheterization in males or females, a 14F or 18F rubber catheter with a 10-mL balloon is satisfactory.  Men with prostatic hypertrophy may require larger catheters (eg, 20-22F).