CRD Flashcards
CRD
Complete Randomized design
A population
The collection of all possible observations of interest
Confounded variables
Variables that are related both to group membership and to the outcome. It’s presence makes it hard to establish the outcome as being a direct consequence of group membership.
A replicate is
A complete set of treatments. Ewes on 2 pasture types = 1 replicate. Another 2 pasture types and set of ewes is the 2nd replicate.
Experimental unit is
The smallest unit to which a treatment has been randomised.
Sampling or observational unit is
The unit at which the measurement is made.
Type 1 Error
Event of rejecting the null hypothesis when it is true. False positive. Saying there are differences when there are not.
Type II error
This is the event of not rejecting the null hypothesis when it is false. It is a false negative, saying that there are not any differences when in fact there are.
Power
Probability of rejecting the null hypothesis when it is false, saying that there are differences when in fact there are differences.
Biggest disadvantage of CRD
Precision is lost, especially for large experiments.
Designed experiments
We assign which treatments to each individual/units.
Observational studied
Observation, not a designed experiment, no treatments set.
Experimental unit
Smallest unit that receives a treatment, completely independent of what other treatments other units receive.
Observational unit
Unit on which observations/measurements are made.
The probability of a type 1 error of a 95% confidence interval is:
5%.
