Edexcel A-Level Biology B 9BI0
Biological Molecules
Cells, Viruses and Reproduction of Living Things
Classification and Biodiversity
Exchange and Transport
Energy for Biological Processes
Microbiology and Pathogens
Modern Genetics
Origins of Genetic Variation
Control Systems
Ecosystems
Ecosystems
Statistical tests in ecology
- 4 things to know
- Papers 2 and 3
Overview
Recall questions on when and how to use the t-test and Spearman's rank correlation coefficient, degrees of freedom and critical values, and calculating the mean, median, mode, range and standard deviation of ecological data.
What you need to know
Answer each one before you reveal it.
What conclusion is drawn if the calculated t-value exceeds the critical value?
After ranking data, what is calculated next for Spearman's correlation?
What is the purpose of a t-test?
Questions from this subtopic
Each one with the model answer underneath.
- 1
What is the purpose of a t-test?
Model answer
To determine whether there is a statistically significant difference between the means of two groups.
- 2
What type of data is required for a t-test?
Model answer
Continuous data.
- 3
What assumption about data distribution must be met for a t-test?
Model answer
The data must be normally distributed.
- 4
What assumption about variance must be met for a t-test?
Model answer
The two groups must have similar variances.
- 5
What must be determined before looking up the critical value for a t-test?
Model answer
The degrees of freedom.
- 6
What does Spearman's rank correlation coefficient measure?
Model answer
The strength and direction of association between two ranked variables.
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