Introduction to BIostatistics in Epi Flashcards Preview

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Flashcards in Introduction to BIostatistics in Epi Deck (34)
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1
Q

3 key attributes of data variables

A
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
2
Q

Nominal

A

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)

3
Q

Ordinal

A

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)

4
Q

Interval/ Ratio

A

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)

5
Q

What type of data is being collected or evaluated?

A

6
Q

What type of comparison/assessment is desired?

A

Correlation!!!! Correlations test.

7
Q

Correlation

A

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….

8
Q

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

A
ordinal= spearman correlation
nominal= contingency coefficent
interval= pearson correlation
9
Q

Contingency coefficent

A

if more than .05 it is not significantly significant

10
Q

Time-to event… event-occurrence

A

survival test… can all be represented by kaplan meier curve

11
Q

Suvival Test

A

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

12
Q

survial tests….

A

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

13
Q

Outcome prediction/association

A

Regression

14
Q

Regression (THE WORD PREDICT!!!0

A

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

15
Q

Regression tests

A

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

16
Q

Frequencies/ counts/ proportions

A

HOW MAN GROUPS!

17
Q

is the datat independent or related

A

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

18
Q

Nominal 2 groups independent data

A

(Pearsons) Chi-square test

19
Q

nominal greater than 3 independent data

A

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

20
Q

nominal >2 groups with expected cell count of <5

A

fisher’s exact test

21
Q

Nominal 2 groups of paired/related data

A

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

22
Q

nominal >3 groups of paired related data

A

cochran ….. must do bonferroni test of inequality

23
Q

Ordinal 2 groups of independent data

A

Mann-whitney test

24
Q

Ordinal data >3 groups of independent data

A

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

25
Q

If related data

A

before and after… beginning and end… baseline vs end

26
Q

Ordnial data 2 groups of Paired data

A

Wilcoxon SIgned Rank test

27
Q

Ordinal >3 groups of paired data

A

Friedman test… do post hoc after

28
Q

Post hoc tests for 3 or more group comparisons

A

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

29
Q

Interval 2 grousp of independent data

A

student t test… compares mean values btw groups

30
Q

interval data >3 groups of independent data

A

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

31
Q

Interval data >3 groups of independent data w cofounders

A

ANCOVA

MANCOVA

32
Q

Interval 2 groups of data paired

A

Paired t test

33
Q

interval data >3 groups of paired data

A
repeated ANOVA
Repeated MANOVA(>2)
34
Q

INterval data>3 paried with cofounders

A

repeated ANCOVA

Reated MANCOVA