Exam Revision Flashcards
What is the third assumption of ANOVA?
The variance is the same in all k populations.
When is it appropriate to use a contingency table?
When the response variable is categorical and the explanatory variable is categorical.
What are the four components of an effective figure caption?
- title
- description of the techniques or methods used
- statement of the main results
- explanation of symbols, error bars or legends
The effects of pesticide and predator presence on tadpole survival were examined. 16 tubs were each filled with four tadpoles. Four tubs were randomly assigned to each combination of treatments (predator & pesticide, predator no pesticide, no predator & no pesticide, no predator and pesticide). What are the independent sampling units?
tubs
What is the second assumption of ANOVA?
The variable is normally distributed in each of the k populations.
When should you use a Tukey-Kramer test?
To test all pairs of means to find out which groups stand apart, following an ANOVA.
When should you use ANOVA?
To compare more than two means to each other. The response variable is numerical and the explanatory variable is categorical.
Define ‘Type II error’.
A Type II error is failing to reject a false null hypothesis.
What are the four goals of graphing?
- Show the data.
- Make patterns in the data easy to see.
- Represent magnitudes honestly.
- Draw graphical elements clearly.
Define ‘P-value’
The P-value is the probability of obtaining the data (or data showing as great or greater difference from the null hypothesis) if the null hypothesis were true.
When is it appropriate to use a mosaic plot?
When the response variable is categorical and the explanatory variable is categorical.
Does randomisation eliminate bias or reduce sampling error?
eliminate bias
Define ‘Type I error’.
A Type I error is rejecting a true null hypothesis. The significance level, alpha, sets the probability of committing a Type I error.
When is it appropriate to use a strip chart?
When the response variable is numerical and the explanatory variable is categorical.
What does a Q-Q plot tell us?
The Q-Q plot shows whether Y is normally distributed across X.
Define ‘variable’.
A variable is a characteristic that differs among individuals.
What is the third assumption of linear regression?
The variance of Y values is equal at all values of X.
When should you use a chi-squared contingency test?
To compare frequencies or proportions to each other. The response variable is categorical and the explanatory variable is categorical.
When should you use a two sample t-test?
To compare two means to each other. The response variable is numerical and the explanatory variable is categorical.
Does blinding eliminate bias or reduce sampling error?
eliminate bias