Biostats

Question 1

mode

Answer 1

most frequent values

Question 2

median

Answer 2

center value arranged from lowest to highest

Question 3

Range

Answer 3

highest - lowest

Question 4

Gaussian or normal distribution curvw

Answer 4

the mean, median, and mode are the same values

Question 5

Skew

Answer 5

refers to the direction of the tail.

left skew (negative): more higher values

Right Skew (Positive): More lower values

Question 6

Null Hypothesis

Answer 6

No statistically significant difference in the groups. what the person tries to reject

Question 7

Alternative hypothesis

Answer 7

There IS a statistically significant difference

what the person tries to prove

Question 8

Confidence Interval

Answer 8

CI = 1 - alpha

if it does not cross 0 or 1 it is significant

Question 9

Type 1 error

Answer 9

False positive = Alpha

Question 10

Type 2 error

Answer 10

False Negative = Beta

Question 11

Power

Answer 11

Power = 1 - Beta

Is determined by outcome values, rate and significance

Question 12

Risk

Answer 12

of unfavorable events in group / Total # in group

Question 13

Relative Risk (RR)

Answer 13

Risk in Txt group / Risk in Control Group

RR = 1 no difference in risk
RR > 1 greater risk of the outcomes
RR < 1 lower (reduced) risk

Question 14

Relative Risk Reduction (RRR)

Answer 14

1 - RR

Measures how much less likely the events risk is in the treatment group relative to the control group

Question 15

Absolute Risk Reduction (ARR)

Answer 15

(% risk in control) - (% risk in treatment group)

Question 16

Number needed to Treat (NNT)

Answer 16

1 / (ARR = % risk in control - % risk in txt)

Always round up no mater what

Question 17

Odds Ratio (OR)

Answer 17

Estimates the risk associated with the treatment or intervention in a case control study

Question 18

Hazard Ration (HR)

Answer 18

Hazard rate in txt group / HR in cont group

Question 19

Discrete Data (Categories)

Answer 19

Nominal (Categorical) Data - ordeer doesnt matter

EX: Sex, ethnicity, marital statis, religous preference

Question 20

Discrete Data (Rank in ORDER)

Answer 20

Ordinal Data - order matters

Ranked categories Ex: NYHA FC Class ranking, Pain scale 8 is worse than 7

Question 21

Continous Data (most measurements)

Answer 21

Ratio Data - meaningful values with a true meaningful 0. 0 = none

EX: Blood pressure ( 0 = death), time, wt, ht

Question 22

Continuous Data

Answer 22

Interval Data - meaningful values but without a meaningful 0

Ex: Temp

Question 23

Student t-test

Answer 23

Assess significance in studies with continuous data

Question 24

Chi-Square Test

Answer 24

Assess significance between treatment groups in a discrete data (nominal or ordinance)

Question 25

Independent variable

Answer 25

is manipulated by the researcher Ex: drug doses, placebos

Question 26

Dependent variables

Answer 26

Comorbidity like HF diabetes, BP,

Question 27

Types of medical Studies

Answer 27

In order of most reliable to least | Systematic review and Meta > RCT> Cohort> case-contolled > case series/report> expert opinion

Question 28

Case-control study

Answer 28

Compares patients with a disease (cases) to those without the disease (control). the researcher looks back retrospectively

Question 29

Cohort Study

Answer 29

Compares outcomes of a patients exposed (txt) and not exposed (control) to a txt. The researcher looks progressively

Question 30

Cross-sectional survey

Answer 30

Estimates the relation between variables and outcomes at one particular time in a defined population

Question 31

Case report/Series

Answer 31

Describing a unique adverse reaction or unique condition that appears in a single patient (report) or few patients (series) Think attridge starting one for the C.Diff bacteremia

Question 32

Randomized controll trial (RCT)

Answer 32

Compares and expiremental treatment to a control (placebo or standard) to determine which is better. Contains Inclusion and exclusion criteria

Question 33

RCT crossover

Answer 33

Group 1 recieves txt a then switches to txt b Group 2 recieves txt b then switches to a

Question 34

RCT factorial

Answer 34

randomizes more than the two usual groups

Question 35

Meta-analysis

Answer 35

Combines results from multiple studies in order ot develop a conclusion that has a greater statistical power than from the smaller studies

Question 36

Systematic Reviews

Answer 36

Summary of the clinical literature that focues on a specific topic or question. Think about the systematic review you included in the letter to the editorial.