Brine shrimp

Jessie · Post by **Jessie** » Tue Dec 30, 2003 9:46 am

I need some help with the most basic part of my science fair project. I am going to study the effect of pH on the growth/life of brine shrimp. I have some good help in the basic process, but am unsure how many brine shrimp I should use in each pH solution. Are there any suggestions/ideas I can get from the experts? I am not sure if I could get some help on this. Thanks.

williamcolocho · Post by **williamcolocho** » Wed Dec 31, 2003 7:46 pm

In general, the bigger the sample size, the better.

One possibility would be to start with a large number of brine shirmp for just 3 pH levels at extreme values. (One at very high pH, one medium pH and one at very low pH). The results of this first run can then help you decide how many brine shirmp to use.

This assumes you have time to do more than one "run" for the experiment.

I did a google search and found this site on statistics and number of samples:

http://www.statsoftinc.com/textbook/stathome.html

Look at:

-Statistical significance and the number of analyses performed
-Why significance of a relation between variables depends on the size of the sample
-Example: "Baby boys to baby girls ratio"
-Why small relations can be proven significant only in large samples
-Can "no relation" be a significant result?

Good luck and let us know if you have more questions.