Factors Influencing the Attainment of Statistical Significance

Between-groups variation in the data. This is an overall measure of how different participants reductions in SBP in the drug treatment group are from those for the control group. 

The total number of SBP reduction values collected in the trial. Since one SBP reduction value was obtained for each participant, this is effectively the total number of participants in the trial. 

Consider the basic task being performed by the statistical analysis in these simple terms we want to know if one group of numbers (SBP reductions in the drug treatment group) is different from a second set of numbers (SBP reductions in the control group). Consider a hypothetical example presented by Turner and Thayer (2001). Group A consists of five numbers and Group B consists of a second set of five numbers  

There are also two other groups of five numbers each  

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