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Study sets matching "biostats"

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Study sets matching "biostats"

47 terms
Biostats
additive rule
multiplicative rule
positive skew
negative skew
OR; mutually exclusive events
AND; independent events
additive rule
OR; mutually exclusive events
multiplicative rule
AND; independent events
27 terms
Biostats
T/F? In a normal standard distrubtion,…
T/F? In a left skewed distribution, th…
T/F? In a left skewed distribution, th…
T/F? In a normal distribution curve, t…
T
F.
T
T
T/F? In a normal standard distrubtion,…
T
T/F? In a left skewed distribution, th…
F.
67 terms
Biostats
Additive rule
Multiplicative rule
Simple random sampling
Systematic sampling
OR
AND
equal chance of selection
pick every 3rd person
Additive rule
OR
Multiplicative rule
AND
174 terms
biostats
probability=
4 steps of hypothesis testing
null hypothesis
random sampling variation
chance
1. making hypothesis... 2. set criteria for decision... 3. gather d…
there is no difference between your sample and the population…
all observed differences are due to chance
probability=
chance
4 steps of hypothesis testing
1. making hypothesis... 2. set criteria for decision... 3. gather d…
47 terms
biostats
Selection bias
Measurement bias
Experimenter Expectancy bias
Lead time bias
sample not representative of population - pick more at random
info presented gives distorted picture - need control group
pygmalion effect - experimenters' expectations perceived by s…
disease discovered sooner, so seem to live longer - use life…
Selection bias
sample not representative of population - pick more at random
Measurement bias
info presented gives distorted picture - need control group
36 terms
Biostats
Sensitivity
Specificity
PPV
NPV
probability that a test detects dz when dz is present... propor…
- true-negative rate... - probability that a test indicates no d…
probability that the person actually has the dz when given a…
- proportion of negative test results that are TN... - probabili…
Sensitivity
probability that a test detects dz when dz is present... propor…
Specificity
- true-negative rate... - probability that a test indicates no d…
42 terms
Biostats
A contingency table is widely used to…
what is the R code to build a continge…
risk difference is defined as?
NNT or NNH can or cannot contain a dec…
the association between 2 categorical variables
table(data~independent,data~outcome)
a measure of the difference between two proportions... (a/(a+b))…
cannot (don't have half a person)... round UP
A contingency table is widely used to…
the association between 2 categorical variables
what is the R code to build a continge…
table(data~independent,data~outcome)
9 terms
Biostats
Crossover trial
Cross sectional trial
Propensity Matching
Open label
...
...
...
...
Crossover trial
...
Cross sectional trial
...
38 terms
biostats
types of variables
mean
median
mode
dichotomous (yes/no, up/down)... categorical/nominal (leukemia t…
average value
middle value
most common value
types of variables
dichotomous (yes/no, up/down)... categorical/nominal (leukemia t…
mean
average value
42 terms
Biostats
Nominal
Ordinal
Interval
Ratio
- Data are coded by a number, name, or letter that is assigne…
- categories are ordered by rank... - Examples: Pain level (e.g…
- Measurements are ordered (like ordinal data) and have equal…
- Ratio: Measurements have equal intervals & There is a true…
Nominal
- Data are coded by a number, name, or letter that is assigne…
Ordinal
- categories are ordered by rank... - Examples: Pain level (e.g…
19 terms
Biostats
Confidence interval for mean
Test statistic for mean
Confidence interval for proportion
Test statistic for proportion
Confidence interval for mean
Test statistic for mean
10 terms
Biostats
95% CI
Relative risk/Risk ratio (RR)... Probabi…
Number needed to treat (NNT)
Odds ratio (OR)... Represents that proba…
-When 95% for estimated DIFFERENCE between groups (or within…
-Probability of an unfavorable event occurring in the tx grou…
NNT = 100 / % ARR... MUST ALWAYS around up this number! (e.g. 3.…
-ratio of two odds, or the ratio of the odds of an event occu…
95% CI
-When 95% for estimated DIFFERENCE between groups (or within…
Relative risk/Risk ratio (RR)... Probabi…
-Probability of an unfavorable event occurring in the tx grou…
8 terms
biostats
alpha
beta
power
chi square test
- related to p-value... - chance that we will have a type 1 erro…
- chance that we will have a type II error - we couldn't reje…
- 1-beta
- use when you have categorical (as opposed to nominal/contin…
alpha
- related to p-value... - chance that we will have a type 1 erro…
beta
- chance that we will have a type II error - we couldn't reje…
36 terms
Biostats
Scientific Method
Descriptive Statistics is also called
Descriptive Statistics
Statistical Inference is also called
Testing and eliminating hypotheses whose predictions are inco…
Exploratory Data Analysis (EDA)
Organization and summarization of data; graphical display to…
Confirmatory Data Analysis (CDA)
Scientific Method
Testing and eliminating hypotheses whose predictions are inco…
Descriptive Statistics is also called
Exploratory Data Analysis (EDA)
47 terms
Biostats
Incidence
Z Score
Crude vs. cause specific mortality
Case-fatality rate
the number of new cases that develop in a population over a c…
Indicates how many standard deviations a given value is from…
Crude mortality rate: # of deaths/total population size... Caus…
# of deaths from a specific disease/# of people affected by t…
Incidence
the number of new cases that develop in a population over a c…
Z Score
Indicates how many standard deviations a given value is from…
Biostats
Relative Risk
Odds ratio
Negative predictive value
Case-control studies
Typically used in *cohort studies*. Risk of a group developin…
Typically used in *case-control studies. * Odds that group wi…
True negatives divided by (true negatives and false negatives)
Observational & *retrospective*... Compares group of people with…
Relative Risk
Typically used in *cohort studies*. Risk of a group developin…
Odds ratio
Typically used in *case-control studies. * Odds that group wi…
147 terms
biostats
biostatistics
evidence based medicine
anchoring
availability
application of statistics and mathematical testing in medicine
using the best information to make decisions about diagnosing…
fix on particular information, think in linear way
strongly influenced by dramatic or unusual cases that are pro…
biostatistics
application of statistics and mathematical testing in medicine
evidence based medicine
using the best information to make decisions about diagnosing…
53 terms
biostats
simple random sampling
systemic sampling
stratified sampling
cluster sampling
each individual has equal chance of being selected
select at regular intervals through ordered list... -pick random…
separate pop into strata based on a characteristic... randomly…
pop already in strata... -randomly select groups of strata
simple random sampling
each individual has equal chance of being selected
systemic sampling
select at regular intervals through ordered list... -pick random…
52 terms
Biostats
Evidence Based Medicine (EBM)
Research Design
Outline Research Designs and Methods
Experimental vs. Observational
incorporates the integration of the best available, clinicall…
Evidence Based Medicine (EBM)
incorporates the integration of the best available, clinicall…
Research Design
58 terms
Biostats
incidence
prevalence
primary disease prevention
secondary disease prevention
# new cases per year / total population at risk
incidence * time
prevention
early detection
incidence
# new cases per year / total population at risk
prevalence
incidence * time
55 terms
biostats
cases
variable
categorical variable
quantitative variable
the subjects/objects we obtain information about (rows of a d…
any characteristic that is recorded for each case
places each case into exactly one of two of more categories
measures/records a numerical value for each case (makes sense…
cases
the subjects/objects we obtain information about (rows of a d…
variable
any characteristic that is recorded for each case
88 terms
Biostats
No implication of relationship
Info on what proportion of population…
Information on time (how fast disease…
Rate as it pertains to total populatio…
Ratio
Proportion
Rate
Crude Rate
No implication of relationship
Ratio
Info on what proportion of population…
Proportion
37 terms
Biostats
Sensitivity
Specificity
Positive predictive value
Negative predictive value
True positives / true positive + false negatives
True negatives / true negatives + false positives
True positives / true positives + false positives
True negatives / true negative plus false negatives
Sensitivity
True positives / true positive + false negatives
Specificity
True negatives / true negatives + false positives
20 terms
Biostats
Cross sectional study
Case- Control Study
Cohort Study
Phase 1
Data from a group of people to assess the frequency of a dise…
Compares a group with a disease to a group without the diseas…
Compares a group with a given exposure or risk factor to a gr…
Small # of healty volunteers- is it safe?
Cross sectional study
Data from a group of people to assess the frequency of a dise…
Case- Control Study
Compares a group with a disease to a group without the diseas…
10 terms
Biostats
Central Limit Theorem
Standard Errors (SE)
Standard deviation (s)
Standard error of the mean (SEM)
n must be > 60, if sample size is large, distribution of samp…
standard deviation of sampling distribution, measures precisi…
measures variability/spread amount individual observations in…
measure of the precision of the sample mean; SEM = s/root(n);…
Central Limit Theorem
n must be > 60, if sample size is large, distribution of samp…
Standard Errors (SE)
standard deviation of sampling distribution, measures precisi…
Biostats
Cross Sectional
Case-control
Cohort
Twin concordance
Data from a group of people to assess frequency of dz at a pa…
Compares a group of people without a dz to a group with dz.…
Compares a group with a given exposure or risk factor to a gr…
Compares frequency with which both monozygotic twins or both…
Cross Sectional
Data from a group of people to assess frequency of dz at a pa…
Case-control
Compares a group of people without a dz to a group with dz.…
48 terms
Biostats
Cross-sectional Study
Case-control study
Cohort study
Phases of a clinical trial
Disease prevelance... Basically it's like looking at a bunch of…
Looks for prior exposure or risk factor... uses odds ratio ... Comp…
Compares a group w/ exposure to group w/o - looks to see if e…
1: yo we healthy, is this shit safe?... 2: Small sick group, is…
Cross-sectional Study
Disease prevelance... Basically it's like looking at a bunch of…
Case-control study
Looks for prior exposure or risk factor... uses odds ratio ... Comp…
72 terms
Biostats
Variation
Variation examples
Epidemiology
Statistics is the cornerstone of publi…
common feature of most organisms ... (may be environmentally inf…
Weight, height, reaction times, aptitudes, and disease resist…
study of the patterns, causes, and effects of health and dise…
risk factors for disease and targets for preventative medicine
Variation
common feature of most organisms ... (may be environmentally inf…
Variation examples
Weight, height, reaction times, aptitudes, and disease resist…
20 terms
Biostats
Sensitivity
Specificity
PPV
NPV
Sensitivity=TP/ (TP+FN)
Specificity=TN/ (TN+FP)
PPV=TP/(TP+FP)
NPV=TN/(TN+FN)
Sensitivity
Sensitivity=TP/ (TP+FN)
Specificity
Specificity=TN/ (TN+FP)
32 terms
Biostats
Cross-Sectional Study
Case-control study
Cohort study
Twin concordance study
Collects data from a group of people to assess the frequency…
Compares a group of people with disease to a group without di…
Compares a group with a given exposure or risk factor to a gr…
Compares the frequency with which both monozygotic and dizygo…
Cross-Sectional Study
Collects data from a group of people to assess the frequency…
Case-control study
Compares a group of people with disease to a group without di…
13 terms
Biostats
When can the mean be used?
What type of data can the mean be used…
Is the mean sensitive to outlying valu…
When should the median be used?
when data is not skewed
continuous data
yes
when data is skewed
When can the mean be used?
when data is not skewed
What type of data can the mean be used…
continuous data
86 terms
Biostats
mutually exclusive
independent
additive rule is for ___... multiplicativ…
ex. complete blood count: probability…
-either OR (NOT both)... ex) heads OR tails
-and (either event could occur)... ex) roll 6 AND 2
add="or"... multi="and"
(0.95)^9
mutually exclusive
-either OR (NOT both)... ex) heads OR tails
independent
-and (either event could occur)... ex) roll 6 AND 2
17 terms
Biostats
Multivariate analysis is used for:
Linear Regression Model
Results of a regression analysis are p…
How to read beta coefficients for line…
looking at more than 1 independent variable at the same time
Use when you have a:... - Continuous dependent variable (ie CD4…
Estimates of population parameters for each of your independe…
If one has an abdominal measurement that is 1 cm greater than…
Multivariate analysis is used for:
looking at more than 1 independent variable at the same time
Linear Regression Model
Use when you have a:... - Continuous dependent variable (ie CD4…
21 terms
biostats
cross-sectional study
case-control study
cohort study
twin concordance study
Assess frequency of disease at a particular point in time. "W…
(retrospective) compares group of people with disease to grou…
(Prospective [who will develop the disease] or retrospective…
compares the frequency of disease development between monozyg…
cross-sectional study
Assess frequency of disease at a particular point in time. "W…
case-control study
(retrospective) compares group of people with disease to grou…
10 terms
Biostats
What is sensitivity?
What is specificity?
100 patient with disease and test dete…
What is the predictive value?
Proportion of subject with disease who test positive
Proportion of subject without disease who test negative
90 / (90 pos + 10 neg) = 90%
help decide whether to believe result for an individual patient
What is sensitivity?
Proportion of subject with disease who test positive
What is specificity?
Proportion of subject without disease who test negative
39 terms
Biostats
What is a variable?
What is an independent variable?
What is a dependent variable?
What are the four data types?
Measurement or description of a characteristic
value known of determined before the study starts... *some inde…
value determined during/after the study
1) numerical/interval continuous distribution... 2) nominal ca…
What is a variable?
Measurement or description of a characteristic
What is an independent variable?
value known of determined before the study starts... *some inde…
146 terms
Biostats
population
sampling
sampling methods
simple random sampling
a complete set of individuals, objects, or events, that share…
a portion of a population selected to represent the populatio…
1) simple random... 2) systematic... 3) stratified... 4) cluster... 5) co…
the simplest form o sampling methods where all members of a g…
population
a complete set of individuals, objects, or events, that share…
sampling
a portion of a population selected to represent the populatio…
28 terms
Biostats
What do the odds ratio and relative ri…
You need to use odds ratio in what kin…
What is one advantage of odds ratios?
The ____ for any event X, considers BO…
When the outcome being analyzed is common; they do approximat…
Case control
It doesn't change depending on whether we focus on the event'…
the Odds
What do the odds ratio and relative ri…
When the outcome being analyzed is common; they do approximat…
You need to use odds ratio in what kin…
Case control
65 terms
BIOSTATS
Deviation score
nominal data
ordinal data
interval data
D=X-x... Distance a number is from the mean
data are placed in qualitative groups... ex. based on descriptio…
data are placed in ranking orders ... ex. 1st, 2nd, 3rd ... DOESNOT…
data are in a meaningful order without an absolute zero... oft…
Deviation score
D=X-x... Distance a number is from the mean
nominal data
data are placed in qualitative groups... ex. based on descriptio…
10 terms
Biostats
What is a type 1 error (alpha)
What is a type 2 error (beta)... What is…
When can a written advance directive b…
In what type of study to you use RR an…
You saw a difference that didn't exist... You say a drug works…
Don't approve a drug when it actually works... Blind to a diff…
Probably never...... For sure not in emergency situation
Prospective cohort studies... Case-control studies
What is a type 1 error (alpha)
You saw a difference that didn't exist... You say a drug works…
What is a type 2 error (beta)... What is…
Don't approve a drug when it actually works... Blind to a diff…
37 terms
Biostats- Guidelines
What are the 3 components of Evidence…
What is the goal of EBM?
What are the sources of evidence in or…
"Systematically developed statements t…
Individual clinical experience, best available clinical evide…
Improved patient outcomes
Systems, Synopses, Systematic Reviews, and Studies
Guidelines
What are the 3 components of Evidence…
Individual clinical experience, best available clinical evide…
What is the goal of EBM?
Improved patient outcomes
24 terms
Biostats
Statistics
Parameter
Estimate
Categorical
study of methods to describe and measure aspects of nature fr…
describes the population (averages, proportions, measures of…
statistic that is subject to error; calculation from a sample
not numbers
Statistics
study of methods to describe and measure aspects of nature fr…
Parameter
describes the population (averages, proportions, measures of…
21 terms
Biostats
Confound variables
Mensurative experiment... vs. Manipulativ…
Random Sampling vs Regular Sampling
3 variables
the experiment design should control for the effect of the co…
measure what exists ... you control the independent variable ... •…
Random: each individual has an equal and independant chance o…
Attribute Ranked Measurement
Confound variables
the experiment design should control for the effect of the co…
Mensurative experiment... vs. Manipulativ…
measure what exists ... you control the independent variable ... •…
63 terms
Biostats
Nominal
categorical
continuous
Dichotomous
a named category (i.e. names of cities)
ordered categories (presented with median and range)
variables that can take on any value in a given range (presen…
categorical variable that can fall into 2 categories only (i.…
Nominal
a named category (i.e. names of cities)
categorical
ordered categories (presented with median and range)
134 terms
Biostats
X
N
n
probability
1 measurement/element
elements in population
elements in sample
positive, decimal or fractions between 0-1
X
1 measurement/element
N
elements in population
31 terms
biostats
standard deviation equation
confidence interval
CI significant for difference if
CI significant for odds/risk/hazard ra…
square root of variance
1-alpha or 1- type I error AVOIDING TYPE I ERROR
doesnt include zero
doesnt include 1
standard deviation equation
square root of variance
confidence interval
1-alpha or 1- type I error AVOIDING TYPE I ERROR
26 terms
biostats
mean
median
mode
range
average... sensitive to outliers... can be used when data is not sk…
middle of ranked list... arrange in order, count... less influenced…
most frequent number
difference between highest and lowest
mean
average... sensitive to outliers... can be used when data is not sk…
median
middle of ranked list... arrange in order, count... less influenced…
226 terms
biostats
cross sectional
case control
cohort study
clinical trial
what is happening... assesses frequency of disease at particul…
what happened?... retrospective... compare people *with dz to tho…
can be prospective or retrospective... asks who will develop, wh…
compares therapeutic beneifts of 2 or more txs or tx vs placebo
cross sectional
what is happening... assesses frequency of disease at particul…
case control
what happened?... retrospective... compare people *with dz to tho…
11 terms
Biostats
Binomial Distribution
Population
Sample
Sampling frame
A random variable has a binomial distribution if it is the nu…
Complete set of entities or elements or units or subjects tha…
A subset of a population
List of items in a population from which a sample is drawn
Binomial Distribution
A random variable has a binomial distribution if it is the nu…
Population
Complete set of entities or elements or units or subjects tha…
7 terms
Biostats
OR
RR
AR
RRR
Case-Control: Odds group with disease was exposed to risk fac…
Cohort: Risk of developing disease in exposed group divided b…
Difference in risk between exposed and unexposed groups... AR =…
Proportion of Risk Reduction attributable to intervention... 2%…
OR
Case-Control: Odds group with disease was exposed to risk fac…
RR
Cohort: Risk of developing disease in exposed group divided b…
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