PT - JOURNAL ARTICLE AU - Thomas A Lang TI - Study Design and Statistical Analysis: A Practical Guide for Clinicians. DP - 2007 Apr 01 TA - Respiratory Care PG - 490--491 VI - 52 IP - 4 4099 - http://rc.rcjournal.com/content/52/4/490.short 4100 - http://rc.rcjournal.com/content/52/4/490.full