STATISTICAL ANALYSIS FOR MEDICAL RESEARCH Using SPSS
Day 1
Determining Sample Size
Mr. Ahmad Alsaber
Example 1: Comparing two means
A placebo-controlled randomized trial proposes to assess the effectiveness of Drug A in preventing the stress response to laryngoscopy. A previous study showed that there is the average rise of 20 mm of Hg in systolic blood pressure during laryngoscopy (with SD of 15 mm of Hg). What should be the sample size to study the difference in mean systolic blood pressure between two groups with a significant P < 0.05 and power of study of 90%.
Research #1
Mr. Ahmad Alsaber
Logistic regression is used to predict a categorical (usually dichotomous) variable from a set of predictor variables.
As an example of the use of logistic regression in psychological research, consider the research done by Wuensch and Poteat and published in the Journal of Social Behavior and Personality, 1998, 13, 139-150.
