PowerPoint Presentation

BiostatisticsChapter 1:IntroductionToBiostatistics

1

Biostatistics

StatisticsStatistics is a branch of applied mathematics that deals with the collection, organization, presentation, analysis and interpretation of data.

StatisticsStatisticians develop and apply appropriate methods in collecting and analyzing data. They guide the design of a research study and then, analyze the results. The interpretation of the results will be the basis in making inferences about the population being considered. StatisticsResearch uses statistics in making conclusions in order to solve the stated problem.

* LEGEND: All green arrows are accomplished by using Biostatistics.Descriptive StatisticsDescriptive Statistics deals with the collection and presentation of data and the summarizing values that describe the groups characteristics. The most common summarizing values are the measures of central tendency and variation.Inferential StatisticsInferential Statistics deals with predictions and inferences based on the analysis and interpretation of the results of the information gathered by the statistician.Some of the common statistical tools of inferential statistics are the t-test, z-test, analysis of variance, chi-square, and Pearson r. VariableA Variable is a numerical characteristic or attribute associated with the population being studied.VariableCategorical/Qualitative Variables -are classified according to attributes.

Examples:Gender, eye color, political reference, religion, blood type, civil status, year level, course, profession and socioeconomic status.VariableB. Numerical/Quantitative Variables -are classified according to numerical characteristics.-can be treated as categorical variables when they are grouped into class intervals.

Examples:Age, height and grade.

Numerical Variableb.1. Discrete Variables -are variables whose values are obtained by counting.

Examples:Number of children, number of persons with blue eyes.

Numerical Variableb.2. Continuous Variables -are variables whose values are obtained by measuring.

Examples:Temperature, distance, age, height and weight.

Scales of MeasurementScales of Measurement -are usually obtained by any method when gathering data.

Examples:Temperature(Celcius), distance(meters), age(years), height(inches) and weight(pounds).

Scales of MeasurementFour Scales of Measurement A. Nominal Scale B. Ordinal Scale C. Interval Scale D. Ratio

Scales of MeasurementNominal Scale -A measurement that classifies elements into two or more categories. The numbers indicate that the elements are different but difference is not according to order.

Examples:ReligionFemale MaleTotal Christian 34 43 77Scales of MeasurementOrdinal Scale -A measurement that ranks individuals in terms of degree to which they possess the characteristic.

Examples:Legend: Anxiety LevelSex 0 1 2 3Male 9 16 2 1Female21 10 4 7Scales of MeasurementInterval Scale -A measurement that in addition to ordering score from highest to lowest establishes a uniform unit in scale so that the distance between 2 consecutive scores of equal magnitude. There is no absolute zero in this scale.

Example:Whole numbers interval of 2 to 10.The answer is 8.Scales of MeasurementRatio -In addition to being an interval scale also has an absolute zero.

Example:Height, weight, volume, speed, area and etc.PopulationPopulation -Define as a group of people, animals, places, things or ideas. Example:Population in the Philippines.PopulationSample -Is a sub-group of population.

Example:Population in the Philippines within the confinement of NCR.PopulationParameter -Numerical measure that describes a characteristic of a population.

Example:Electricity bills of the residence of Makati City is 1,300 php. per month.PopulationStatistics-Numerical measure that describes a characteristic of a sample.

Example:The sample mean of IQ of 35 students in a certain university is 105.

BiostatisticsFIN