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The purpose was twofold. Firstly, usually we will get a sample and do one preparation and one measurement. We want to be able to give a margin for error on the measurement we provide to the client. For example, if we measure the a-pinene to be 2.63938, should we say plus or minus 0.001, or...

Most of this conversation is going over my head because I'm not a statistician, but one thing I'm curious about is why the data wouldn't be a normal distribution? It seems like it should be, so I'm wondering if it just doesn't look normal because I don't have enough samples?

Ok thanks for your input. For the record, I cut and pasted straight from excel, it was the website that interpreted it as an image. Is this confidence interval based on 95% confidence? Also, if I work this out for all compounds, then work out the confidence interval as a percentage of the...

No, the tea tree oil is distilled already. It's all one source, already bottled. I just made three preparations to determine if my preparation process introduces variation. The other variation is in the injection and measurement process in the Gas Chromotographer.

Hi, I work in a phytochemistry lab where substances are analysed by gas chromotography to estimate quantities of individual compounds in a sample. I want to work out how much variation there is in our process. To do so, I prepared three samples from the same source of tea tree oil, and...