BAOBAB

HI Brendan, Fionnuala and Toby

I have been checking the salmple 15 and I'm trying to identify the way the student got the data. The aim of the research is to found the relation of size of mussles with the distance they are from the shore; in this way is trying to take samples of mussles at different distances of the intertidal zone in order to determine how the exposure to sunlight and presence of predators reduce their size.

Had classified in three sizes: small (0 - 2,5 cm) medium (2,5 - 3,5 cm) and large (> 3,5 cm) up to there I found is fine, but the moment of explaining how to get the data is confusing how mark the distance fromo the pole to the shhore, and in what ratio the random samples of 25 mussles must be selected.

The hypothesis is fine but the confussion starts at the moment of determining how data must be collected.

I wait for your comments

BAOBAB - Use this page to discuss marks for your specific sample.

Hi - Toby here - I was intrigued at the size classifications. Why did the student divide the mussels up into three categories? Wouldn't it have been better, and far less arbitrary, to measure absolute sizes and do Spearman's rank of size against distance? Also, how were the mussels selected, the student says it was done randomly but there is no mention of using a random number table nor of how the sites were selected (systematic and random sampling). 25 is a very small number to measure! I wonder how long it took? I quite liked the discussion of other abiotic factors, including the effects of sunlight over the convex wave-breaker. Toby. BTW using this Wiki is MUCH easier than the Moodle interface. Thanks for this. Toby