# Study sets matching "biostats"

Study sets

Diagrams

Classes

Users

the process of statistics involves:

collection of ALL individuals or inform…

that PART of the population which you o…

# describing a population

1. have a question/goal... 2. collect data... 3. describe, organize…

population

sample

parameter

the process of statistics involves:

1. have a question/goal... 2. collect data... 3. describe, organize…

collection of ALL individuals or inform…

population

Adjusted rate (Adjustment)

alpha

type 1 error

Analysis of covariance (ANCOVA)

Standardization; a procedure in which the effects of differenc…

the probability of a type 1 error

rejecting the null when its true

Originally used for an extension of the analysis of variance t…

Adjusted rate (Adjustment)

Standardization; a procedure in which the effects of differenc…

alpha

the probability of a type 1 error

probability=

4 steps of hypothesis testing

null hypothesis

random sampling variation

chance

1. making hypothesis... 2. set criteria for decision... 3. gather da…

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 da…

Standard deviation

Prevalence

Incidence

Crude (Overall) Mortality Rate (CMR)

Used for symmetric measured data

# of ALL cases of a particular disease in a population... # case…

# of NEW cases of a disease in a population... # of new cases in…

# of deaths/ total population size... Measures the overall death…

Standard deviation

Used for symmetric measured data

Prevalence

# of ALL cases of a particular disease in a population... # case…

null hypothesis

types of data

meristic data

mensural data

-prediction that no cause and effect will be evident in the da…

-meristic... -mensural... -categorical

count data

anything measured in standard units

null hypothesis

-prediction that no cause and effect will be evident in the da…

types of data

-meristic... -mensural... -categorical

Hypothesis

Null hypothesis

Alternative hypothesis

Conditions

'a testable prediction drawn from a theory'

'the hypothesis has no effect (eg: the thing you're trying to…

'the hypothesis is correct and has an effect'

'total number of experimental groups in study'

Hypothesis

'a testable prediction drawn from a theory'

Null hypothesis

'the hypothesis has no effect (eg: the thing you're trying to…

4 steps of hypothesis testing

null hypothesis

alternative hypothesis

probability of "normal" on a CBC

Make hypothesis... Set criteria for decision... Gather data and cond…

No difference... All samples from same population... Observed differ…

At least one sample from different population... Difference not d…

95%

4 steps of hypothesis testing

Make hypothesis... Set criteria for decision... Gather data and cond…

null hypothesis

No difference... All samples from same population... Observed differ…

null hypothesis

alternative hypothesis

the likelihood of finding a difference…

how to calculate Confidence Interval

states that there is no difference

states that there is a difference

p value

=1-Type 1 error

null hypothesis

states that there is no difference

alternative hypothesis

states that there is a difference

Cross sectional study

Case- Control Study

Cohort Study

Phase 1

Data from a group of people to assess the frequency of a disea…

Compares a group with a disease to a group without the disease…

Compares a group with a given exposure or risk factor to a gro…

Small # of healty volunteers- is it safe?

Cross sectional study

Data from a group of people to assess the frequency of a disea…

Case- Control Study

Compares a group with a disease to a group without the disease…

Sensitivity

Specificity

PPV

NPV

probability that a test detects dz when dz is present... proport…

- true-negative rate... - probability that a test indicates no di…

probability that the person actually has the dz when given a p…

- proportion of negative test results that are TN... - probabilit…

Sensitivity

probability that a test detects dz when dz is present... proport…

Specificity

- true-negative rate... - probability that a test indicates no di…

Nominal data

Ordinal data

kinds of data in nonparametric tests

Types of tests associated with ordinal…

Comparing modes between groups

comparing medians between groups

Nominal and Ordinal

Mann-whitney U test... Wilcoxan Signed Rank test ... Kruskai wallis…

Nominal data

Comparing modes between groups

Ordinal data

comparing medians between groups

Statistics defintion

Descriptive statistics

Inferential statistics

Parameter

-Numerical properties of groups rather than individuals... -Colle…

Deals with techniques for summarizing and presenting data and…

deals with methods for assessing uncertainties in data estimat…

a characteristic of apopulation under study

Statistics defintion

-Numerical properties of groups rather than individuals... -Colle…

Descriptive statistics

Deals with techniques for summarizing and presenting data and…

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 description…

data are placed in ranking orders ... ex. 1st, 2nd, 3rd ... DOESNOT…

data are in a meaningful order

**without**an absolute zero... ofte…Deviation score

D=X-x... Distance a number is from the mean

nominal data

data are placed in qualitative groups... ex. based on description…

cross sectional study

cross sectional study

case control study

case control study

collets data form a group of people to assess frequency of dis…

for disease prevlanece

compares a group of people with disease to a group witout dise…

to calcualte odds ratio

cross sectional study

collets data form a group of people to assess frequency of dis…

cross sectional study

for disease prevlanece

When can the mean be used?

What type of data can the mean be used…

Is the mean sensitive to outlying value…

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

Guidelines for stem and leaf plots

Ordinal variable

Nominal variable

Discrete variable

# of bins: Sqrt (N), ... Interval #: # of bins/range

Ranks data, uses numbers only to indicate ranking. One where t…

...

a variable that can only take on certain values on the scale

Guidelines for stem and leaf plots

# of bins: Sqrt (N), ... Interval #: # of bins/range

Ordinal variable

Ranks data, uses numbers only to indicate ranking. One where t…

95% CI

Relative risk/Risk ratio (RR)... Probabil…

Number needed to treat (NNT)

Odds ratio (OR)... Represents that probab…

-When 95% for estimated DIFFERENCE between groups (or within t…

-Probability of an unfavorable event occurring in the tx group…

NNT = 100 / % ARR... MUST ALWAYS around up this number! (e.g. 3.0…

-ratio of two odds, or the ratio of the odds of an event occur…

95% CI

-When 95% for estimated DIFFERENCE between groups (or within t…

Relative risk/Risk ratio (RR)... Probabil…

-Probability of an unfavorable event occurring in the tx group…

Normal Distribution (p. 176)

Standard Deviation

Skewness (p. 177)

Null Hypothesis (H0) (p. 177)

1. Bell shaped curve... 2. Gaussian curve... Features:... 1. mean, med…

1 std deviation: 68%... 2 std deviations: 95%... 3 std deviations: 9…

Direction of skewness refers to the direction of the LONGER ta…

states that there is NO difference between groups... Like no dif…

Normal Distribution (p. 176)

1. Bell shaped curve... 2. Gaussian curve... Features:... 1. mean, med…

Standard Deviation

1 std deviation: 68%... 2 std deviations: 95%... 3 std deviations: 9…

case control

increasing sample size will

Cohort Study

Risk difference

subjects enrolled based on disease status, one gorup with dise…

NARROW the confidence interval

subjects enrolled based on EXPOSURE status.

the risk difference between two groups... risk in exposed- risk i…

case control

subjects enrolled based on disease status, one gorup with dise…

increasing sample size will

NARROW the confidence interval