# 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

Cross Sectional Study... (observational)

Cross Sectional Study measures

Case Control Study... (observational and r…

Case Control Study measures...

collects data from group of people to assess frequency of dise…

disease prevalence... shows risk factor association with disease,…

compares a group of people with disease to a group without dis…

odds ratio... Ex: patients with COPD have higher odds of a histor…

Cross Sectional Study... (observational)

collects data from group of people to assess frequency of dise…

Cross Sectional Study measures

disease prevalence... shows risk factor association with disease,…

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…

What type of data is classified into gr…

What type of data is ranked in a specif…

What type of data can take on any value…

What type of continuous data has a cons…

Nominal... Ex: disease presence: "yes or no"

Ordinal... Ex: Likert scales, NYHA functional class

continuous data

Ratio

What type of data is classified into gr…

Nominal... Ex: disease presence: "yes or no"

What type of data is ranked in a specif…

Ordinal... Ex: Likert scales, NYHA functional class

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…

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

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…

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…

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…

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…

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

# variables for one-sample t-test

What question does a one-sample t-test…

steps for hypothesis testing

Null hypothesis for one-sample t-test

1 numeric

Does the sample mean significantly differ from from the popula…

1. assumptions... 2. hypotheses... 3. find t... 4. find t*... 5. conclusion

mu = [number]

# variables for one-sample t-test

1 numeric

What question does a one-sample t-test…

Does the sample mean significantly differ from from the popula…

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

Cross-sectional study

Case-control study

Cohort study

Twin concordance study

Assess frequency of dz & RF at a point in time... Simultaneous de…

Compare a group w/ dz to a group w/o dz ... RETROSPECTIVE: Look f…

Compares group w/ given exposure/RF to group w/o exposure ... PRO…

Compares frequency w/ which MZ/DZ twins develop same dz... Measur…

Cross-sectional study

Assess frequency of dz & RF at a point in time... Simultaneous de…

Case-control study

Compare a group w/ dz to a group w/o dz ... RETROSPECTIVE: Look f…

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…

Directional hypotheses

Non-directional hypotheses

Type 1 error

Type 2 error

believes a (specific) relationship exists. "subjects who repor…

"Pain will be related to healing time". Non specific.

false positive. Occurs when you incorrectly reject the null hy…

false negative. Occurs when you incorrectly except a null hypo…

Directional hypotheses

believes a (specific) relationship exists. "subjects who repor…

Non-directional hypotheses

"Pain will be related to healing time". Non specific.