How to Compare Two Groups of Data

A knowledge of basic statistics is important for the researcher.

Compare your data:

Many research studies are controlled studies which attempt to compare an experimental group to a control group. For example: An experimental group would be the group of patients that receive a new treatment as the control group would receive the standard treatment.

For comparisons to be valid the two groups should be either selected randomly or in some studies they are matched. The groups should be as similar as possible.

Statistical Differences are described as the probability that the observed differences could occur by chance alone. For a Statistically Significant Difference to occur, the probability that the observed difference could occur by chance alone should be less than one in twenty or a p value of less than 0.05.

If the results can be grouped into a few categories, such as yes vs, no; or another example: red vs. white vs. green, then a Chi Square Test may be performed to determine if the two groups are different. More About The Chi Square Test

If the results are in a continuous data category such as weight or survival after a diagnosis, then a t-test may be able to determine if the two groups are statistically different by comparing the data's mean and standard deviation. More About Paired T-Test