Prompt Six - On Design Essay Example | Topics and Well Written Essays - 250 words

Prompt Six - On Design - Essay Example This is also referred to as a cross over study. It allows for a comparison of the results arising from different tests performed on the same group of subjects. For example, in a test comparing the effects of a low glycemic load (LGL) diet with a high glycemic load (HGL) diet the same group is fed with a LGL meal in one instance and a HGL meal in another instance. There are advantages and disadvantages to both approaches. In the ‘between groups’ approach participants are less likely to become bored as in the ‘within group’ approach because they are only used for one treatment. Therefore, they are more likely to entertain follow up treatments than is the case with the ‘within group’ approach where participants may not complete the tests. The ‘within group’ is less costly when compared to the ‘between groups’ approach as it involves only one group on which more than one treatment is administered while the ‘between groups’ approach require more than one group. Therefore, the number of participants subjected to tests are half as much as in the ‘between groups’ approach. Additionally, the ‘within group’ approach is less error prone since the same subjects are used for both tests whiles the ‘between groups’ approach is negatively imp acted by individual differences. The effect of the first treatment on the second treatment is a major disadvantage of the ‘within group’ approach. The main differences between the two approaches need to be clearly understood in order to facilitate a determination of the statistical tests to be employed so that inferences can be made. Paired t-Tests is useful in analyzing ‘within group’ designs while independent t-Tests is useful for analyzing data for ‘between groups’