Maths Flashcards
1
Q
When should the chi-squared test be used?
A
- Frequencies
- Collecting data about the number of individuals in particular categories
- Eg. Genetic cross experiments, choice chamber behavioural studies or count number of individuals of different species.
2
Q
How do you do the chi-squared test?
A
- Degrees of freedom = number of categories - 1
- Compare calculated and critical at the value of 0.5 significance
- Calculated is greater than critical then reject the hypothesis as a significant difference not due to chance.
3
Q
When should you use the student T-Test?
A
- Collecting data that are measurements
- Looking for differences between measurements of the same variable from different samples
- Eg. two different environments same DV but different IV.
4
Q
How do you use the student T-Test?
A
- Degrees of freedom = number in sample 1 + number in sample 2 - no. of samples.
- Compare the calculated value of T and critical value at p=0.05
- If calculated is greater or equal to critical then reject the null hypothesis - less than 5% probability that the difference between mean values are due to chance
5
Q
When should I use the Spearman Rank test?
A
- Collecting data that are measurements
- Looking for a correlation between measurements of the different variable from the sample.
- Eg. leaf length and leaf width correlation or nitrogen conc and length of invertebrate.
6
Q
When should the index of diversity be used?
A
- Will be told to use!!
- Investigate the species richness in a community
7
Q
What is normal distribution?
A
Bell shaped curve of continuous variation eg. height or weight
8
Q
What is the mean?
A
max height of normal distribution curve
9
Q
What is standard deviation?
A
distance from mean when curve change from being convex to concave - gives measure of range of value on either side of mean.