Biostatistics Lecture Notes 2024 PDF

Lectures of Biostatistics Prepared By: Assoc. Prof. M. A. Alawady Department of Mathematics Faculty of Science Zagazig University 2024 Lecture (1) Introduction To Biostatistics 2 ◼ Key word...

Lectures of Biostatistics Prepared By: Assoc. Prof. M. A. Alawady Department of Mathematics Faculty of Science Zagazig University 2024 Lecture (1) Introduction To Biostatistics 2 ◼ Key words : ◼ Statistics , data , Biostatistics, ◼ Variable ,Population ,Sample 3  Introduction Some Basic concepts Statistics is a field of study concerned with 1- collection, organization, summarization and analysis of data. 2- drawing of inferences about a body of data when only a part of the data is observed. Statisticians try to interpret and communicate the results to others. 4  * Biostatistics: The tools of statistics are employed in many fields: business, education, psychology, agriculture, economics, … etc. When the data analyzed are derived from the biological science and medicine, we use the term biostatistics to distinguish this particular application of statistical tools and concepts. 5 Data: The raw material of Statistics is data. We may define data as figures. Figures result from the process of counting or from taking a measurement. For example: - When a hospital administrator counts the number of patients (counting). - When a nurse weighs a patient (measurement) 6  * Sources of Data: We search for suitable data to serve as the raw material for our investigation. Such data are available from one or more of the following sources: 1- Routinely kept records. For example: - Hospital medical records contain immense amounts of information on patients. - Hospital accounting records contain a wealth of data on the facility’s business - activities. 7 2- External sources. The data needed to answer a question may already exist in the form of published reports, commercially available data banks, or the research literature, i.e. someone else has already asked the same question. 8 3- Surveys: The source may be a survey, if the data needed is about answering certain questions. For example: If the administrator of a clinic wishes to obtain information regarding the mode of transportation used by patients to visit the clinic, then a survey may be conducted among patients to obtain this information. 9 4- Experiments. Frequently the data needed to answer a question are available only as the result of an experiment. For example: If a nurse wishes to know which of several strategies is best for maximizing patient compliance, she might conduct an experiment in which the different strategies of motivating compliance are tried with different patients. 10  * A variable: It is a characteristic that takes on different values in different persons, places, or things. For example: - heart rate, - the heights of adult males, - the weights of preschool children, - the ages of patients seen in a dental clinic. 11  Types of variables Quantitative Qualitative Quantitative Variables Qualitative Variables It can be measured Many characteristics are in the usual sense. not capable of being For example: measured. Some of them - the heights of can be ordered or adult males, ranked. - the weights of For example: preschool children, - classification of people into - the ages of socio-economic groups, patients seen in a - social classes based on - dental clinic. income, education, etc. 12  Types of quantitative variables Discrete Continuous A discrete variable A continuous variable is characterized by can assume any value within a gaps or interruptions specified relevant interval of in the values that it values assumed by the variable. can assume. For example: For example: - Height, - The number of daily - weight, admissions to a - skull circumference. general hospital, - The number of No matter how close together the decayed, missing or observed heights of two people, filled teeth per child we can find another person whose height falls somewhere in an in between. elementary 13 school.  * A population: It is the largest collection of values of a random variable for which we have an interest at a particular time. For example: The weights of all the children enrolled in a certain elementary school. Populations may be finite or infinite. 14 * A sample: It is a part of a population. For example: The weights of only a fraction of these children. 15