Biostatistics Notes PDF

# Biostatistics - **Introduction to Biostatistics** - **Definition:** Biostatistics is the application of statistical methods to biological, medical, and health-related studies. - **Statistical Methods:** Techniques used for collecting, analyzing, interpreting, and presenting data. - **...

# Biostatistics - **Introduction to Biostatistics** - **Definition:** Biostatistics is the application of statistical methods to biological, medical, and health-related studies. - **Statistical Methods:** Techniques used for collecting, analyzing, interpreting, and presenting data. - **Biological Measurement:** Quantitative or qualitative data collected in biological research (e.g., height, weight, or disease prevalence). - **Kinds of Biological Data** 1. **Qualitative Data:** Non-numeric (e.g., gender, blood type). 2. **Quantitative Data:** Numeric; subdivided into: 3. **Discrete Data:** Countable values (e.g., number of cells). 4. **Continuous Data:** Measurable values (e.g., height, temperature). ## Measures of Central Tendency 1. **Mean:** The average of all data values. * Formula: Mean = ∑x / n, where ∑x = sum of all values, and n = number of observations. 2. **Median:** The middle value in an ordered dataset. * If n is odd, median is the middle value; if even, it is the average of the two middle values. 3. **Mode:** The most frequently occurring value in a dataset. ## Standard Deviation (SD) * **Definition:** A measure of data dispersion around the mean. * Formula: where = mean, = each value, and = sample size. ## Collection of Data - **Primary Data:** Directly collected by the researcher through experiments, surveys, or observations. - **Secondary Data:** Previously collected data from sources like publications or databases. ## Sampling and Sampling Design - **Sampling:** Process of selecting a subset (sample) from a population for study. - **Types of Sampling:** 1. **Random Sampling:** Every individual has an equal chance of selection. 2. **Stratified Sampling:** Population divided into subgroups, and samples are taken proportionately. 3. **Systematic Sampling:** Selecting every nth individual from a list. 4. **Cluster Sampling:** Dividing the population into clusters and sampling entire clusters. ## Classification and Tabulation - **Classification:** Organizing data into categories or classes based on characteristics. - **Tabulation:** Presenting classified data in a systematic table format for analysis. ## Types of Representation - **Textual Representation:** Describes data in words. - **Tabular Representation:** Organizes data into rows and columns. - **Graphical Representation:** Presents data visually for easier interpretation. ## Graphical Biodiagrams - **Bar Diagrams:** Used for comparing discrete data. - **Pie Charts:** Represents proportions of a whole. - **Histograms:** Displays frequency distribution for continuous data. - **Line Graphs:** Shows trends over time. - **Scatter Plots:** Depicts relationships between two variables.