The complete course of biostatics and presentation in detail, Summaries of Biostatistics

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Introduction to Module 5/17/2024 Basic Biostatistic OBAID ULLAH FAHIM MD, MPH, PHD 7 Time 6:00 - 8:00 Saturday, Monday, Wednesday 5/17/2024 Course Objectives: • Understand the basic concepts of inferential statistics including probability, confidence intervals, and hypothesis testing. • Know when and how to apply common parametric and none parametric statistical tests 5/17/2024 Course contents: I will share it with you in separate file 5/17/2024 Method of Teaching: Lecture and Discussion group 5/17/2024 Objectives At the end of this lecture student will be able to explain: Statistic, Biostatistics, data and Variable 5/17/2024 | Why Do I Need Biostatistics in My Life? 5/17/2024 Statistics! “I keep saying that the sexy job in the next 10 years will be statisticians,” said Hal Varian, chief economist at Google. “And I’m not kidding.” Hal Varian , Google Chief Economist, August 2009 5/17/2024 Introduction Some Basic concepts Statistics  Recorded data Number of OPD visits and deaths in a hospital  Characteristics calculated for a set of data Mean, standard deviation and correlation coefficient 5/17/2024 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. 5/17/2024 Type of Statistics:  Descriptive statistics: Enumeration, organization and graphical presentation of data, such as in census  Inferential statistics: Use information obtained from sample to say something about an entire population, like in sample survey 5/17/2024 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. Sources of Data: 5/17/2024 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. Sources of Data: 5/17/2024 3- Surveys: The source may be a survey, if the data needed is about answering certain questions. Sources of Data: 5/17/2024 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. Sources of Data: 5/17/2024 How many legs does this elephant have? 5/17/2024 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. 5/17/2024 A discrete variable is occur when the variable can only take certain whole numerical values For example: - The number of daily admissions to a general hospital, - The number of decayed, missing or filled teeth per child in an elementary school. Type of quantitative variable: 5/17/2024 A continuous variable can take any value within a specified relevant interval of values assumed by the variable. For example: - Height, weight, skull circumference. No matter how close together the observed heights of two people, we can find another person whose height falls somewhere in between. Type of quantitative variable: 5/17/2024 A nominal variable(There is no order to the categories.) used as identifiers ;do not represent a quantity like telephone number, zip code, ID and so on. For example:  Ethnicity  1: African American  2: Caucasian  3: Hispanic Type of qualitative variable: 5/17/2024  Outcome /dependent variable  Explanatory variables or( independent variable, risk factor, exposure and predictor)  Examples Smoking  lung cancer Age Hypertension Variable types 5/17/2024 • Independent variables are those that are manipulated and/or may affect the outcome of interest. • These typically include age, gender, and ethnicity. • Dependent variables are the outcomes of interest. – These typically include health status, use of health services, and cost of care. Variable types 5/17/2024 • Independent variables are those that are manipulated and/or may affect the outcome of interest. • These typically include age, gender, and ethnicity. • Dependent variables are the outcomes of interest. – These typically include health status, use of health services, and cost of care. 5/17/2024  Ordinal  Numbers represent categories that can be placed in a meaningful numerical order (e.g., from lowest to highest).  There is no information regarding the size of the interval between the different values.  The size of the interval may be different between the different categories.  There is no “true” zero.5/17/2024  Interval  Numbers can be placed in meaningful order.  The intervals between the numbers are equal.  It is possible to add and subtract across an interval scale.  There is no true zero, so ratios cannot be calculated. 5/17/2024  Ratio  Numbers can be placed in meaningful order.  The intervals between the numbers are equal.  There is a “true” zero, determined by nature, which represents the absence of the phenomena.  Almost all biomedical measures (weight, pulse rate, and cholesterol level) are of ratio scale.5/17/2024