Lab 6: Quantitative vegetation anlysis: species assocaitaion and the X2 Test

Question 1

Statistical methods are largely based off of these 2 assumptions:

Answer 1

1. ) The individuals of a species are randomly dispersed with respect to one another
2. ) These same individuals are randomly dispersed with respect to any environmental gradients/changes.

Question 2

X2=

Answer 2

(O-E)^2/E

Question 3

If X2 is greater than the p it is

Answer 3

rejected, reject the null hypothesis. There is a significant difference between the observed and the expected values.

Question 4

e=

Answer 4

Independent probability of specieis a X independent probability of specieis b X sample size

Question 5

In bivaraite situations what degree of freedom do you use?

Answer 5

1

Question 6

X2 (bivariate situation)=

Answer 6

((ad-bc)^2 N) / (a+b)(c+d)(a+c)(b+d) or do chi-square for each square and add them up!

Question 7

When do we use Coles coefficient equation?

Answer 7

when we rejected the null hypothesis

Question 8

What does it mean if you get a positive or a negative answer using coles coefficient equation?

Answer 8

Positive means: Almost always grow together

Negative means: almost always never together