The vast majority of animals that ever existed are now extinct, but Tereza Jezkova and John Wiens wondered which variables were most important in driving the diversification of species that exist today. Why are there so many species in some phyla, such as Cnidaria (see photo), but so few in others, such as Ctenophora? A sample of Jekova and Wiens' results is shown here. The R2 value represents the strength of the correlation (where 0.00 is lowest and 1.00 is highest). The P value represents the statistical significance. Which five traits look most important?

Video transcript

Hi everyone. Let's look at our next problem. It says the strength of correlation R squared In which 0.00 is the lowest and 1.0 is the highest measures the proportion of variation in the dependent variable that can be attributed to the independent variable. Once the strength of the correlation are identified, for example, your size versus temperature. It must be subjected to analysis for statistical significance p value to identify that the correlation is not attributable by chance. Hence the importance of a specific trait for the organism's adaptation to existing environmental conditions. Suppose we determine the strength of correlation R. Squared and the traits corresponding significant significance. P. Value which of the following traits is considered the most important. So this is a lot of words and we have a chart of different characteristics along with an R. Squared value and a piece value. But kind of what we want to remember here is the higher the R squared value, the greater the correlation of the dependent value are variable. Excuse me. And then the lower the P value the greater the statistical significance. This is cool. That's because the P value represents the probability that your result is due to random chance. So you want that value to be low to show that you have a low probability that your result is just due to chance. And usually the cut off here is you want to see a p value That is less than 0.05 to prove statistical significance. So what we're looking for is a higher R squared and lower p value. So let's look at these different characteristics. We see presence of a skeleton have separate sexes, bilateral symmetry. Have mobile lifestyle and terrestrial life. Well, we'll go ahead and highlight the highest R squared value we see here Which is 0.78 on terrestrial life. And let's look at the high highest P value we see excuse me the lowest P value we see which is presence of a skeleton. Well they're not the same thing. So let's look first at terrestrial life which is the highest correlation. But it's P value is greater than 0.5. And when the P value is greater than 0.5 We would say it's not statistically significant. Therefore we can't say that that variation isn't due to random chance. So we're going to have to cross off terrestrial life just because we can't say that that's not just random chance showing that correlation. So let's look here and we'll find what's the next greatest R. Squared. Well that's 0.61 for presence of a skeleton. So now for presence of a skeleton we have um high R. Squared value. And when we look at our other values it's quite a bit higher. And our P value here is 0.3. So very low so that is definitely statistically significant. So we can say that choice the presence of a skeleton would be the most important trait for the organism's adaptation to the existing environmental conditions, since it shows the highest correlation and the lowest p value indicating statistical significance. See you in the next video.