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.