Term
Hypothesis testing is an extension of what? 

Definition


Term

Definition
A statement (prediction) about one or more populations. 


Term
What is the difference between research and statistical hypotheses? 

Definition
Research  the conjecture that motivates the research (these lead to stat. hyp.) Statistical  are stated in such a way that they may be evaluated by appropriate statistical techniques 


Term
Describe "the whole process" for research 

Definition
1.State the biological problem and define your population of interest 2.Decide on what kind of data, treatments, methods, assumptions, etc. are necessary 3.Formulate a protocol 4.Perform a Pilot Study 5.Collect Data 6.Analyze the Data 7.Interpret the Results 


Term
Our hypothesis comes in a set of what two hypotheses? 

Definition
Null Hypothesis and Alt hypothesis **Hyp are always based on pop parameters, not sample stats** 


Term
Hypotheses can be formulated to test for what 3 patterns? 

Definition
An effect in either direction (not equal) An effect in one direction (< or >) A directional effect of a certain minimum size (AB=2) 


Term

Definition
rejecting Ho when it is true 


Term

Definition
accepting Ho when it is untrue 


Term
What does a nondirectional hypothesis specify? 

Definition
That only an effect exists (the pvalue is expected to be different) 


Term
What does a directional hypothesis specify? 

Definition
The value of one group is expected to be greater than another group 


Term
Is a directional or nondirectional hypothesis more powerful? 

Definition
A directional hypothesis is more powerful, but if there is a difference in the direction not specified, the difference won't be found 


Term
Define "significantly different" 

Definition
More different than we would expect simply due to random chance (he says we must specify this carefully) 


Term
What happens to stat sig as N increases? 

Definition
We expect less variation due to chance 


Term
Absence of evidence is not evidence of absence 

Definition
That is all. I don't know how to put that in a question. 


Term
We can only make statistical claims regarding which hypothesis? 

Definition
The null one (fail to reject Ho and reject Ho) his example was the judicial system 


Term

Definition
α = Pr(Type I Error) = Pr(false positive) β = Pr(Type II Error) = Pr(false negative) Classical hypothesis testing controls α and β is decided afterward – ‘Posthoc’
These values are inversely proportional, but as N increases, both a and B decrease 


Term

Definition
Power = 1 – β And power is the prob of rejecting the Ho given that the Ho is actually false 


Term
Describe the biological assumptions for a statistical test 

Definition
1) all observations are random and unbiased 2) all obs are random 3)All samples are representative of the population 4) The populations are normally distr 5) pops are identical in all characteristics aside from the mean 


Term
Which statistical test do you use for mean? Median? 

Definition
t statistic; MannWhitney U statistic 


Term
What happens to the t distribution as you increase df? 

Definition
The curve becomes more narrow and tall. 


Term
What does your p value mean? 

Definition
The probability of obtaining a teststatistic value as extreme or more extreme than the observed value from the data, assuming the null hypothesis is true. 


Term
What is the posterior power of a test? 

Definition
Symbolized by beta, it is the inverse of pvalue and indicates the power of a test. 


Term
When do you fail to reject Ho? 

Definition
When p value is greater than a 


Term
What kind of hypothesis test do you run on nonindependent samples? 

Definition


Term
Name 3 methods of pairing data for paired comparison test 

Definition
 same experimental unit before and after treatment littermates of same sex randomly assigned to 2 treatments  matching experimental units based on characteristic related to the measure of interest (weight, blood pressure) 


Term
Disadvantages of paired comparisons are: 

Definition
 lots of time and expense finding pairs  loss of df (would have been 2n2, now it's n1) 


Term

Definition
is a statistical technique where the total variation present in a set of data is partitioned into 2 or more components. You can determine the magnitude of different class variables contributing to the toal variation. 


Term
What are the 2 purposes of ANOVA? 

Definition
(1) Estimate and test hypotheses about population variances (2) Estimate and test hypotheses about population means (we’ll focus mostly on this) 


Term
What are 2 sources of variation? 

Definition
Total variation = model variation + residual variation 


Term
What are the assumptions of ANOVA? 

Definition
1. Normal distribution 2. Independence of errors (obs are not infl by each other) 3. Homoscedasticity (homogeneity of variances) 

