Introduction to BIostatistics in Epi

Question 1

3 key attributes of data variables

Answer 1

Magnitude(biger is more, lower is less)
Consistency of scale(or fixed intervals)
-equal, measurable spacing btw units
rational zero
Each can be answered with yes or no repsonse

Question 2

Nominal

Answer 2

Dichotomouse/binary; no order or rank; non ranked categories…. NO magnitude, NO consistency of scale, NO rationonal zero….. examples…. gender, occupationsoal class, party affiliation (ALL dichotomous and non-ranked categories)

Question 3

Ordinal

Answer 3

Ranked Categories; non-equal-distance… YES magnitude, NO consitency of scale, NO rational zero… Rank of canidates in order of preference from worse to best…( all ranked categories)

Question 4

Interval/ Ratio

Answer 4

YES magnitude, YES consitency of scale, NO or YES rational zero (no-interval; yes-ratio) ex… number of living sibilings and age… (all numerical scales with ture units)

Question 5

What type of data is being collected or evaluated?

Answer 5

…

Question 6

What type of comparison/assessment is desired?

Answer 6

Correlation!!!! Correlations test.

Question 7

Correlation

Answer 7

Provides a quantitative measure of the strength and direction of a relationship btw variables…. creates a 45 degree angle…. X goes down, Y goes up….

Question 8

Correlation….. Is the correlation linear? if not significanlty significan then there is NOT linear correlation

Answer 8

ordinal= spearman correlation
nominal= contingency coefficent
interval= pearson correlation

Question 9

Contingency coefficent

Answer 9

if more than .05 it is not significantly significant

Question 10

Time-to event… event-occurrence

Answer 10

survival test… can all be represented by kaplan meier curve

Question 11

Suvival Test

Answer 11

ordinal=cox proportional hazards
nominal= log-rank
interval= kaplan-meier product-limit estimate

Question 12

survial tests….

Answer 12

compares the proprtion of, or time to event occurence btw groups….

Question 13

Outcome prediction/association

Answer 13

Regression

Question 14

Regression (THE WORD PREDICT!!!0

Answer 14

Provide a measure of the relationship btw variables by allowing the prediction about the dependent, or outcome, variable (DV) knowing the value/rank of others independent variables….. able to calculate measerue of associateions

Question 15

Regression tests

Answer 15

Nominal=logistic regression
ordnial= multinominal logistic regression
interval= linear regression

Question 16

Frequencies/ counts/ proportions

Answer 16

HOW MAN GROUPS!

Question 17

is the datat independent or related

Answer 17

Data from the same( paired) ore different groups(independent)?

Question 18

Nominal 2 groups independent data

Answer 18

(Pearsons) Chi-square test

Question 19

nominal greater than 3 independent data

Answer 19

Chi-square test of independence… no cell with expected count of <5…. to predeict 3 more comparisons, one must perform subsequent analysis(post-hoc testing) to determine which groups are different…. Multiple Chi tests NEVER acceptable…. Bonferroni test of Ineqaulity, ver conservative

Question 20

nominal >2 groups with expected cell count of <5

Answer 20

fisher’s exact test

Question 21

Nominal 2 groups of paired/related data

Answer 21

McNemar test…. key words… pre vs post… before vs after, basline vs end

Question 22

nominal >3 groups of paired related data

Answer 22

cochran ….. must do bonferroni test of inequality

Question 23

Ordinal 2 groups of independent data

Answer 23

Mann-whitney test

Question 24

Ordinal data >3 groups of independent data

Answer 24

Kruskal wallis test…. compares the mdeian values btw groups…. mujst perform post hoc

Question 25

If related data

Answer 25

before and after… beginning and end… baseline vs end

Question 26

Ordnial data 2 groups of Paired data

Answer 26

Wilcoxon SIgned Rank test

Question 27

Ordinal >3 groups of paired data

Answer 27

Friedman test… do post hoc after

Question 28

Post hoc tests for 3 or more group comparisons

Answer 28

Student-Newman Keul test - comapres all pairwise comparisons possilbe
Dunnett Test- compares agains single.. equal in size
Dunn Test- Compares all possilbe comparisons

Question 29

Interval 2 grousp of independent data

Answer 29

student t test… compares mean values btw groups

Question 30

interval data >3 groups of independent data

Answer 30

ANaysis of Varainace (ANOVA) (1DV)- comapres menas of all groups
Multiple Analysis of Variance (Manova) (>2 DVs) must do post hoc

Question 31

Interval data >3 groups of independent data w cofounders

Answer 31

ANCOVA

MANCOVA

Question 32

Interval 2 groups of data paired

Answer 32

Paired t test

Question 33

interval data >3 groups of paired data

Answer 33

repeated ANOVA
Repeated MANOVA(>2)

Question 34

INterval data>3 paried with cofounders

Answer 34

repeated ANCOVA

Reated MANCOVA