variables affecting blood pressure

Great work! But I have a question for you. Just because some people are thin, it doesn't mean that they exercise and diet carefully. Did you determine whether the thin people in your experiment actually lead healthy lifestyles? Otherwise, there could be a gap in your project that needs to be addressed.

You should provide as complete a list of materials as possible. For example, you should mention the number of people you need in the MATERIALS section. And as frivolous as it may sound, it would be good to also include writing material.

Could you also explain your results a little more? What was the variance like? And when you took the blood pressure, did you take more than 1 reading per person (for each time that you measured his/her pressure?) and average out the readings or did you just take 1 reading?