Stats and Modeling

Question 1

What is stats used for?

Answer 1

discern justifiable differences in quantitative patterns

Question 2

What are some examples of stats tests?

Answer 2

Basic t-tests, ANOVA, Chi-squared (X2) are
useful

Question 3

How many outcomes do Chi-squared tests measure?

Answer 3

Two

Question 4

When are these basic stats tests too burdensome?

Answer 4

situations where multiple variables and their interactions are in question/confounding!

Question 5

T-tests

Answer 5

This tests whether significant differences, not attributable to random chance, are present in continuous data

Question 6

X2 Test

Answer 6

Test significance between groups of non-continuous data.
Infected vs. not infected, or vaccinated vs. non-vaccinated. Useful with 2 x 2 contingency tables.

Question 7

Fisher’s Exact test

Answer 7

This tests for significance in much the same way as Chi-squared test does, but works with any size data set. It also gives an “exact” P-value, rather than an approximation; Applicable to 2x2 tables.

Question 8

Multivariable regression

Answer 8

Multiple independent variables are regressed on a single dependent variable. All variables are considered together to discern correlations either individually or in combinations

Question 9

Multivariate analysis (MVA)

Answer 9

Techniques allow more than two variables to be analyzed at once

Question 10

What is not usually included under MVAs?

Answer 10

Multiple regression is not typically included under this heading, but can be thought of as a multivariate analysis

Question 11

Two general types of MVA technique?

Answer 11

Analysis of dependence and analysis of interdependence

Question 12

Analysis of dependence

Answer 12

Where one (or more) variables are dependent variables, to be explained or predicted by others; E.g.: Multiple regression, PLS, MDA

Question 13

Analysis of interdependence

Answer 13

No variables thought of as “dependent”; Look at the relationships among variables, objects or cases; E.g. : cluster analysis, factor analysis

Question 14

What is important to bring to statistician?

Answer 14

The question you are trying to answer

Question 15

In most cases data analysis is done to test?

Answer 15

the association between two or more variables (bivariate)

Question 16

In health research the aim is to establish the association between?

Answer 16

risk factor and disease or between therapy and outcome

Question 17

Simple linear regression

Answer 17

Y = a + bX

Question 18

Y

Answer 18

Dependent variable

Question 19

a

Answer 19

intercept

Question 20

b

Answer 20

slope/regression coefficient (change in Y with a one unit
change in X)

Question 21

Multiple Linear Regression equation example

Answer 21

predictor value

Question 22

Multiple linear regression model

Answer 22

Y=a+b1X1+b2X2+b3X3 + ..

Question 23

What is the slope of the regression line mean?

Answer 23

Strength of correlation

Question 24

Model

Answer 24

A set of theoretically and or evidence based associations between variables

Question 25

What does data analysis test?

Answer 25

the extent to which
the proposed theoretical associations are observed in the data

Question 26

What is model development based on?

Answer 26

Previous knowledge (previous research evidence about associations) and new and hypothetical ones.

Question 27

What is model development about?

Answer 27

It is mostly about deciding which independent variables (risk factors) should be in the multivariate analysis.

Question 28

What does SIR stand for?

Answer 28

Susceptible, infectious, recovered

Question 29

Susceptible S(t)

Answer 29

Disease susceptible people in population

Question 30

Infectious I(t)

Answer 30

Those capable of transmitting an infection to others

Question 31

Recovered R(t)

Answer 31

Those that have been infected and recovered

Question 32

Kermack-McKendrick Model Assumptions

Answer 32

Assumes a well-defined and closed and infective and this lasts the duration of the disease state. An infective person is instantly infective and this lasts the duration of the disease state. Homogenous population with no genetic variation or demographic differences.

Question 33

What does a vaccine do to a SIR model?

Answer 33

Takes people from susceptible to recovered