HYPOTHESIS

DESCRIPTIVE STATISTICS

frequencies

basic measurements

normal distribution

* probability distribution that is symmetric about the mean, that the data is centered around the mean, less frequent occurence of observations happen outside mean


* bell shaped curve, symmetric and mesokurtic

gaussian curve

bell shaped curve of normal distribution

following characteristics shall be met

1. mean should always be at the center of curve.
2. must be unimodal (1 mode)
3. must have a predictable strandard deviation
4. symmetric

positive skewed

right skewed

negative skewed

left skewed

kurtosis

4th movement in statistics

* measures peakedness (+leptokurtic) or flatness(-platykurtic) of the data set
* normally distributed data shoulf be mesokurtic having a value of 3.

leptokurtic curve

positive kurtosis, higer pic longer tail

platykurtic curve

negative kurtosis, low peak, shorter tails

hypothesis

predition of relationship between one or more vriables and the problem under study

* to measure relationship among variables need to be identifies
* represents what the researchers think will hapepen in the experiment
* provide the framework of reporting the inferences of the study

null and alternative hypothesis

types of hypothesis

null hypothesis

* egenerally denoted as Ho
* the researchers try to disprove, reject, nullify
* defines the statement which states that there is non exact/actual relationship between variables

alternative hypothesis

* H1
* there is a difference - things are different from each other
* suggests that the experimental/independent variable has an effect on the dependent variable

independent variable

cause

dependent variable

effect

steps to follow statistical hypothesis testing

1. analyze the problem
2. formulate null and alternative hypothesis
3. determine the tails of the test
4. determine the test to be used (statistical test)
5. compute
6. conclude

one tailed hypothesis

* drug a si better/worse than drug b
* there is a bad/good effect of mount pinatuo’s eruption on the landscape of angeles, pampanga
* outcome is expected in a signle direction
* we are interested in the direction of any difference

two tailed hypothesis

* the direction of the effect is unknown
* difference between treatments, but we do not state which way it will go
* drug a has significant difference than drug b
* there is an effect of the mt pinatubo’s eruption on the landsape of angeles pampange

level of significance

* maximum probability of committing error
* greek letter alpha
* can have 2 tails or 1 tail depending on problem and hypothesis
* 0.10, 0.05, 0.01

parametric test

rely on assumptions about the shape of the distribution normal distribution in the underlying population and about the form of parameters (man, SD) of assumed distribution

* based on distribution
* infromation of puplation is known
* uses mean
* tests:
* 1 sample t test
* 2 sample t test
* one way ANOVA

non parametric tests

* rely on no or few assumptions about the shape or parameters of the population distribution from which the sample was drawn
* refer to a statistical method in which the data is not required to fit a normal distribution.
* • uses data that is often ordinal, meaning it does not rely on numbers, but rather on a ranking or order of sorts.

drawing conclusion

the calculated value is compared to the critical value to determine if the difference is significant enough to reject Ho at the predetermined level of significance

* if critical value > calculated value then do not reject Ho (accept Ho)

t test

parametric test used to test significant difference

paired t test

determine whether the mean of the differences between two paired samples differs from 0 (or target value)

* calcualtes

ANOVA

* aparametric test used to test the significant difference of 3+ groups
* method of testing the quality of 3+ population means by analyzing sample variations
* equal no of respondents in ech group
* unequal no of respondents in each group

pearson r

* continuos (noral distribution, relationship,correlation)
* ex.
* parametric used in determining relationship between 2 sets of data
* qualitative description of coefficient relation
* Positive: increase in one variable will result to an increase of another, and vice versa
* Ex: as age increases, the weight increases •
* Negative correlation: negative r value. Increase of one will result in decrease of another •
* Ex: The more people are vaccinated, the less that illness occurs

spearman rank correlation

nonparametric used to find out if there is a significant relationship between 2 variables

DEMOGRAPHY

* statistical study of human population
* encompasses the study of size, structure, and distribution of populations
* spatial/temporal changes in response to birth, migration, aging and death

demographics

characteristic of a population

population

study of character, no and distribution of living organisms

* social science
* biological science
* size of breeding groupd

factors in population

social science

* relationships, politics, sa isang lugar

biological science

* birth death

size of breeding group

dami ng babae sa lugar

* computation of vital and health statistics rates and ratios
* setting up coverage of activities
* setting up norms for assignment of health facilities, staff, and funds

principal uses of population data in health administration

description of population

variables and observation

variable

* chaacteristics that can change values from case to case (gender, income, age, political party affilication)
* 2 types
* dependent variable
* independent

dependent variable

variable whose variation depends on other variable

observation/cases

entity from which data are collected; also known as unit of analysis (individuals, households, states, countries)

formal demography

* development and application of new methods for the analyses of demographic data
* comprises a set of techniques by which data collected in censuses, surveys and vital registration systems about age, sex, birthds, deaths, migration, marriages
* analyzing components of population change

social demography

* encompasses the study of feritility mortality, politics, migration
* study of reasons for changes in population and its structures and their results

population studies

study of fertility mortality and migration

continuous population registration (CPR)

* consist of registering births, deaths. emigration and immigration, making necessary additions and - to the existing population
* mathematical estimates
* arithmetic increase method
* geometric increase method

arithmetic increases method

assumed that the population increases at a constant amount per year

* +100 000 people per year

geometric increase method

assume that population increases at a constant rate per year

* +10% per year

natural increase

difference between the number of births and the number of death occuring in a population in a specified period of time

* number of births- no of deaths

rate of natural increase

* difference between crude birth rate and crude death rate on a population in a specific amount of time
* CBR-CDR

CEnsus

* official and periodic enumeration of population
* common direct method of collecting demographic data conducted by a national govt and attempts to enumerate every person in a country
* 5 yrs
* not the best source of data on births and deaths

* de jure method
* de facto method

census

de jure method

* done when people are assigned to the place where they usually live regardless of wher they are at the time of the census

de facto method

done when the people are assigned to the place where they ar physically present at the time of census regardless of their usual place of residence

sample survey

* specific data are gathered
* may happen anytime a needed
* use in policy analysis and election
* on a small population

direct method

* comes from vital statistics registries that track all births and deaths
* changes in legal status (marriage divorce)
* migration (registration of pace of residence)
* administered throu the use of an interviewer or self-enumerated

indirect method

* required in countries where full data are not available
* sister method techqnieuq - where survey researchers ask women how many of their sisters have died or children and at what age
* other indirect methods include asking people abt sibling parents children
* data are not collecter initially for statistical purposes but can be orgnized to produce statistics

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key measures in demography

chi square

• A non parametric that test the comparison between 2 variables. •Normality distribution is not required.\`

kruskal wallis (h test)

* Non parametric test that uses ranks of sample data from three or more independent populations.
* • It is the counterpart of ANOVA
* • Assumptions
* 1. We have 3 different independent samples, all of which are randomly selected
* 2. Each sample has at least 5 observation each
* 3. No requirement of having a normal distribution or any particular distribution.

crude birth rate

The annual number of live births per 1,000 people

age specific fertility ate

The annual number of live births per 1,000 women in particular age groups (usually age 15 19, 20 24 etc.)

net reproduction ratio

expected number of daughters, per mother, taking mortality into account

total fertility rate

• average number of children a woman would have

replacement level fertility

• average number of children a woman must have in order to replace herself with a daughter in the next generation

gross reproduction rate

• number of daughters who would be born to a woman completing her reproductive life.

general fertility rate

annual number of live births per 1,000 women of childbearing age (often taken to be from 15 to 49 years old, but sometimes from 15 to 44).

crude death rate

• annual number of deaths per 1,000 people

infant mortality rate

annual number of deaths of children less than 1 year old per 1,000 live births

expectation of life/life expectancy

number of years which an individual at a given age could expect to live at present mortality levels.

fertility

number of years which an individual at a given age could expect to live at present mortality levels.

mortality

• is the study of the causes, consequences, and measurement of processes affecting death to members of the population.

migration

• is the study of the causes, consequences, and measurement of processes affecting death to members of the population.

sex composition

• To describe the sex composition of the population, the nurse computes for the sex ratio.

• The sex ratio compares the number of males to the number of females in the population using the formula below

• The sex ratio represents the number of males for every 100 females in the population

* median age
* dependency ratio

age composition

median age

divides the population into two equal parts.

• if the median age is 19 years old, it means half of the population belongs to 19 years and above, while the other half belongs to ages below 19 years old.

dependency ratio

compares the number of economically dependent with the economically productive group in the population.

* -• The dependency ratio represents the number of economically dependent for every 100 economically productive.

economically dependent

0-14 and 65 above age groups.

economically productive

those within the 15-64 age group.

AGE AND SEX COMPOSITION

• described at the same time using a population pyramid. - It is a graphical presentation of the age and sex composition of the population.

population distribution

* can be described in terms of urban rural distribution, population density and crowding index.
* • The measures help how resources can be justifiably allocated based on concentration of population in a certain place.

urban rural distribution

• simply illustrates the proportion of the people living in urban compared to rural areas.

crowding index

• described by number of persons in a household divided by the number of rooms used by the family for sleeping.

population density

Population density is defined as #of People divided by Land area

epidemiology

Study of the distribution and determinants of health-related states among specified populations and the application of that study to the control of health problems

• Disease was due to evil spirits

• Recovery was attributed to good spirits

• Disease as a form of punishment

• Control measures include offering sacrifices and “casting- out demons”

theories of disease causation

germ/bacteriological theory

• Koch confirmed Pasteur’s previous claims

• Disease is due to microscopic forms of life

• Opened the concepts of isolation and quarantine

• Measures to destroy and remove the bacteriological cause such as disinfection , fumigation and general cleanliness

• Bacteriology – explained the origins and spread of communicable disease

filth theory

• Associates disease with the physical environment

• Disease change with seasons, climate, temperature, overcrowding and filth

• Diseases were due to poisonous substances and gases from the earth

• “Bad air”

concept of multiple causation

Disease results from the interaction of multiple ecologic factors within a dynamic system made up of an agent of disease, host and the environments

the web

States that effects never depend on single isolated causes but rather develop as the result of chains of causation result of complex genealogy and antecedents

epidemiologic lever

* The host and agent are at the opposite ends of a hypothetical lever while the environment serves as the fulcrum
* Based on biologic laws:
* Disease results from an imbalance between disease agent and man
* The nature and extent of the imbalance depends on the nature and characteristics of the host and the agent
* The characteristic of the two are influenced considerably by the conditions of their environment

environment

* external to the host and in which the agent may exist, survive, or originate
* Can be physical, climatologic, biologic, social and economic
* It may enhance or diminish survival of agent. It may also serve to bring agent and host into contact.

reservoirs

\- medium that fosters the survival of infectious disease agent.

* o An individual or animal infected with a pathogenic microbe is called a Reservoir host.
* o Human reservoir hosts can be patients, personnel, or visitors and include those with an active disease, those incubating a disease, and chronic carriers of a disease.

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* human reservoir
* animal reservoir

reservoirs

animal reservoir

• Zoonotic diseases •

infectious diseases of animals that can cause disease when transmitted to humans.

- rabies

\- plague

agent of disease

•any element, substance, or force whether living or non-living, the presence or absence of which can initiate or perpetuate a disease process

•2 types: Living and Non-living

•Characteristics:

* o Inherent Characteristics
* o Characteristics directly related to man
* o Characteristics related to the environment

physical features

biologic requirements

inherent characteristics (2)

physical feature

• include morphology, motility, presence or absence of capsule, spore or cyst forms

biologic requirements

• refers to the things needed by agent to survive

• Ex. some are aerobic, anaerobic, capnophilic

infectivity

o the ability of an agent to invade and multiply in a host.

o Example:

* o infection of high infectivity: measles
* Infection of low infectivity: leprosy
* dependent on a number of factors including viability, portal of entry, susceptibility of the host, susceptible tissues and body defenses of the host.

pathogenicity

* ability to produce clinically apparent illness.
* dependent on factors such as dosage, presence or absence of capsule, degree of toxigenicity, condition of the host

virulence

severity of the reaction produced and measured in terms of fatality