Chi-squared (4.3)

Question 1

Give the definition of a species niche

Answer 1

All of the environmental factors and interspecies relationships that influence a singular species.

Question 2

Define the following adaptations: behavioural, physiological and anatomical. Give specific examples for each.

Answer 2

Behavioural: actions carried out by the organism (feeding behaviour, parenting style, etc)

Physiological: internal body processes within the cell or tissues, for an organism to survive in the environment (metabolic rate and storage of minerals and energy, etc)

Anatomical: structures that can be seen when we observe/dissect an organism (webbed feet, extra organs, etc)

Question 3

Give the formula for chi-squared

Answer 3

x^2 = £ (O-E)^2 / E

X^2 = test statistic
£ = sum of
O = observed frequencies
E = expected frequencies (frequencie added / number of categories)

Question 4

Explain which critical value to compare chi-squared to

Answer 4

To find the correct critical value to compare your chi-squared result to, you must find the degrees of freedom. To do this you simply take 1 away from the number of categories you have, move down the degrees of freedom on the table displayed and across to the right significance level.

Question 5

State when you accept or reject the null hypothesis.

Answer 5

If calculated number (chi-squared) is larger than critical value, reject null hypothesis. If lower than critical value, accept the null hypothesis.