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Sample size with 2 techniques - (Sep/24/2012 )

Hi all. I will start a research project including flow cytometry and immunohistochemistry marker X, but I dont know how to calculate the sample size that should be used in the study. Must be different depending on the technique? What kind of formula could use? If someone could guide me, it would be greatly appreciated

-Kikyou_-

You need to consider before you start - is the data likely to be normally distributed, or are you likely to have a low number (<30) replicates - if the answer to either of these is yes, then you will probably need to use non-parametric statistics.

The exact test you will use depends on what you want to show, how many variables you are trying to examine....etc.

-bob1-

Thanks for your feedback. Similar publications, used sample sizes between 15 and 30 individuals, however I don't know the type of formula used to calculate that sample size and the parameter using to calculate (precentrage of receptor expression, in cytometry?)

-Kikyou_-

There is no formula for calculating sample size - the sample size you have is the number of different samples you use in your experiments. If you have fewer than 30 samples you need to use non-parametric statistics.

The parameters you use are up to you - you should discuss this with your supervisor and/or a FACS expert, not some random guy off the internet...

-bob1-