Nature of Probability and Statistics Essay

descriptive statistics consists of the befoolion, organization, summarization, and presentation of data. Inferential statistics consists of generalizing from samples to peoples, performing estimations hypothesis testing, find relationships among variables, and making predictions. (Probability, Hypothesis testing, relationships between variables, predictions) Probability is the play of an event occurring. A population consists of all subjects that argon being studied. A sample is a free radical of subjects selected from a population.Variables and Types of Data In order to grow knowledge about seemingly haphazard events, statisticians collect information for variables that describe the events. A variable is a diagnostic or attribute that washbowl imbibe different values. Data argon the values that variables sight suck up. A data set is a charm of data values. Each value in the data set is called a data value or a datum. Random variables have values that argon mouldd by h ap. 1 M227 Chapter 1 genius of Probability and StatisticsQualitative variables can be set into distinct categories according to some characteristic or attribute. quantitative variables be numerical in disposition and can be ordered or ranked. Quantitative variables can be further classified into cardinal groups. o Discrete variables assume values that can be counted. o Continuous variables can assume all values between any two specific values. (Discuss boundaries ex. recorded height of 73 has edge of 72. 5 ? x 73. 5 ) Levels of MeasurementVariables are classified by how are organized, counted, or heedful Nominalclassifies data into mutually exclusive (nonoverlapping), difficult categories in which no order or be can be imposed on the data. ordinalclassifies data into categories that can be ranked however, dead differences between the ranks do not exist. Intervalranks data, and precise differences between units of measure do exist however, on that point is no meaningf ul zero. Ratiopossesses all the characteristics of interval measurement, and there exists a true zero. Data disposition and Sampling TechniquesSurveys are the most common method of collecting data. Three methods of descrying are o Teleph mavin surveys o Mailed questionnaire surveys o in the flesh(predicate) interviews Direct Observations or surveying records Methods to obtain so-so(p) samples o Random samples are selected using chance methods or random methods. o Systematic samples are obtained by numbering each subject of the population and then selecting every kth number. o Stratified samples are obtained by dividing the population into groups according to some characteristic that is important to the study, then sampling from each group. clod samples are obtained by using intact groups called clusters. twain main ways to classify statistical studies In an observational study, the researcher merely observes what is happening or what has happened in the past and tries to dra w conclusions based on these observations. In an experimental study, the researcher manipulates one and only(a) of the variables and tries to determine how the manipulation influences other variables. 2 M227 Chapter 1 record of Probability and Statistics Statistical studies usually include one or more in bloodsucking variables and one dependent variable.The independent variable in an axperimental study is the one that is being manipulated by the researcher. The independent variable is similarly called the explanatory variable. The rsultant variable is called the dependent variable or the random outcome. Uses and Misuses of Statistics Detached statistics Implied connections Misleading graphs Faulty survey questions Computers and Calculators In the past, statistical calculations were done with pencil and paper. However, with the advent of calculators, numerical computations became easier. Excel, MINITAB, and the TI-83 graphing calculator can be use to perform statistical computati ons.