Average for results

AFTER you've done your research and concluded your experiments, it is time to prepare for the science fair. Ask specific questions about preparing for a science fair, including how to set up your display board, how to prepare a presentation, etc. (Please post questions about selecting a project or conducting your experiment by posting in the appropriate "area of science" forum.)

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kscrane
Posts: 2
Joined: Thu Feb 28, 2013 12:38 pm
Occupation: Parent of 5th grader
Project Question: My son is finishing his science project on Fruit DNA extraction. He's comparing strawberries, kiwi and banana, with a hypothesis that higher polyploid fruit will yield more dna. He did 10 extractions of each fruit. He's wondering if he should average all 10 numbers, or if he should drop the highest and lowest, then average the remaining 8 numbers. Is there a preferred method?
Project Due Date: March 6, 2013
Project Status: I am finished with my experiment and analyzing the data

Average for results

Post by kscrane »

My son is doing the Fruit DNA extraction for his science fair project. He's tested three fruits, 10 times each. Our question is, should he average all 10 results for each fruit, or should he throw out the high and low and average the remaining 8 ? Would this be more accurate? Is there a preferred method? Thanks!
arasson
Former Expert
Posts: 10
Joined: Fri Jan 18, 2013 1:23 pm
Occupation: UCLA PhD student researcher
Project Question: to be an expert
Project Due Date: n/a
Project Status: Not applicable

Re: Average for results

Post by arasson »

Hi kscrane,

Thats a great project! Unless you think there are outliers for more reason other than natural varience, I think it would be better practice to leave all the data points in your analysis. The only concern I have is about the amount of starting materials. The different fruits have different water weight so even if you are starting with the same weight of each fruit you may not have the same amount of fruit material that you are working with. Is this something that you have taken into consideration? If not, than it will be difficult to confirm that the different amount of DNA extracted was due to the polypoidy of the fruit or if you just started with different amounts of materials.

I hope this helps!
kscrane
Posts: 2
Joined: Thu Feb 28, 2013 12:38 pm
Occupation: Parent of 5th grader
Project Question: My son is finishing his science project on Fruit DNA extraction. He's comparing strawberries, kiwi and banana, with a hypothesis that higher polyploid fruit will yield more dna. He did 10 extractions of each fruit. He's wondering if he should average all 10 numbers, or if he should drop the highest and lowest, then average the remaining 8 numbers. Is there a preferred method?
Project Due Date: March 6, 2013
Project Status: I am finished with my experiment and analyzing the data

Re: Average for results

Post by kscrane »

Thank you! We did not take water weight into account, and that may explain his results. The triploid banana just edged out the hexaploid kiwi, and the octoploid strawberry had the smallest average (although they were all relatively close). Do you have to either prove or disprove a hypothesis? Can his conclusion say that it's "inconclusive" and question water weight?
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