Free, public mindmap - Subscribe to Mindmup Gold to save private maps and more File Insert Edit View Help SIGN UP You have unsaved changes in this map SIGN IN PUBLISH SAVE inference are made entire collection of entities that we POPULATION want information about "all" subset of population SAMPLE what we examine to less complicated, less gather information costly, and time-saver "randomly selected" Plural Sense: collection of facts and figures or processed data (numerical figures) based on population average - ratio and POPULATION MEAN: μ intervals PARAMETERS POPULATION characteristics PROPORTION: P Example POPULATION STANDARD DEVIATION: σ dispersed SUMMARY MEASURES POPULATION proximity and spread dispersed VARIANCE:σ^2 out based on sample SAMPLE MEAN: x̄ STATISTICS SAMPLE PROPORTION: p̂ Example SAMPLE STANDARD DEVIATION: s SAMPLE VARIANCE: s² categorical data that cannot be measured on QUALITATIVE a natural numerical scale characteristic or attribute that is measured for the unit age, number of siblings, TYPE under consideration DISCRETE recorded on a natural finite or countable number of values number of courses example failed, time spent studying occurring numerical QUANTITATIVE scale and performs arithmetic operations infinitely many values CONTINUOUS at any point of a given example height, weight, weekly allowance interval qualitative variable gives names/ labels to various categories without a sense of order NOMINAL categories are of equal importance data are limited to frequency counts and percentages VARIABLE sex, employment status, farm type, example tenure status, yes or no question qualitative variable inherent ordering difference between categories cannot be measured and has no meaning ORDINAL Module 1 n = number of trials Symbols Basic Concepts in Inferential Statistics limited to frequency counts and percentages Statistics LEVEL OF MEASUREMENT example p = probability of failure p1^x = 0.1 x = probability of success X = probability of events quantitative variable Singular Sense: branch of science (theory and methods) intervals between categories have meaning xi = number of times outcomes k occurred in n trials INTERVAL cannot perform multiplication or division 2 possible outcomes MEAN number of trials are fixed; n > 1 BINOMIAL DISTRIBUTION E[X] = np FORMULAS VARIANCE2 (standard deviation) constant for each trial (independent) means doesn't affect other trials V[X] = [np (1-p)] P(X<x) = P(X=x) + P(X=x)... may also depends if the x is too big P(X>x) = 1 - P(X<x) IQ scores, degree Celsius, fahrenheit example SD[X] = √[np (1-p)] quantitative variable has an absolute zero point = absence all POSSIBLE outcomes are known in advance X ~ binomial (n,p) P(X=x) = (nCx)(p^x)(1-p)^(n-x) highest educational attainment, satisfaction rating, student classification associated with discrete random variable, which can take on distinct, countable, sometimes infinite number of values PROBABILITY MASS FUNCTION P(X>x) = P(X=x) + P(X=x)... RANDOM EXPERIMENT/ STATISTICAL EXPERIMENT DISCRETE PROBABILITY DISTRIBUTION properties RATIO outcomes are unpredictable ACCURATE OBSERVATION repeatable KEYWOARDS SAMPLE SPACE more than 2 outcomes number of trials are given RANDOM VARIABLE constant for each trial (independent) means doesn't affect other trials PROBABILITY MASS FUNCTION realized value of a variable that is measured and recorded DATA rule that quantifies each of the outcome (let x be.... = {0,1,2,..} Common Probability Distributions ESTIMATOR BRANCHES OF STATISTICS (objectives: to define and to infer) INFERENTIAL STATISTICS bell-shaped formula for computing ESTIMATION finding a value or range of values for an unknown parameter of interest numerical value ESTIMATE range of plausible values between 0 and 1 P-value extreme or even more extreme CONFIDENCE INTERVAL ESTIMATION statement about the parameter associated with continuous random variables, which can take any value on an interval NORMAL DISTRIBUTION TEST OF HYPOTHESIS verifying a claim interval becomes CONFIDENCE INTERVAL if a confidence coefficient is attached to it format CONTINUOUS PROBABILITY DISTRIBUTION smallest standard error obtained by selecting the appropriate statistic symmetric in mean = median = mode maximum = mean minimum asymptotic tails measured by variance or standard error single value POINT ESTIMATION COMMON PROCEDURES IN STATISTICAL INFERENCE closeness to the different possible values PRECISE BASIC CONCEPTS conclusions apply whether it is a population or sample data tools used to analyze the information from the sample to make generalizations from the population PROPERTIES kelvin tools used to describe a mass of data Module 2 bias = zero, then the estimator is unbiased measured by bias collection of observation on one or more variables DESCRIPTIVE STATISTICS PROBABILITY DISTRIBUTION most quantitative falls in ratio example set of all possible outcomes of a random experiment (Ω) MULTINOMIAL DISTRIBUTION gives probabilities of occurrence of the possible outcomes of a random experiment closeness to the true value can multiply or divide 1-α α = level of significance 0% = no confidence 100% = certain level of confidence 90%, 95%, 99% higher degree of confidence = wider interval point estimate (+-) standard error FORMAT: Ho: Population Parameter = null value HYPOTHESIS NULL HYPOTHESIS reject Ho each unit in the population has a known and nonzero chance of selection PROBABILITY MASS FUNCTION z = look at the z-table always less than point estimator of the population is the sample mean (x̄ ) x̄ /n POINT ESTIMATOR normally distributed or approximates a normal distribution SIMPLE RANDOM SAMPLING draw lots STRATIFIED RANDOM SAMPLING example indicates accuracy length is the precision (standard error) GOALS STAT 101 collect data for decision making equal chances contradictory statement that will be accepted if the Ho is rejected ALTERNATIVE HYPOTHESIS reject a true Ho take a sample in every groups(cluster) SYSTEMATIC SAMPLING x̄ +- Margin Error Formulating the hypothesis FORMAT Test procedures SAMPLING METHOD CLUSTER SAMPLING CONFIDENCE INTERVAL ESTIMATOR Sampling frame make the group (clusters) chosen a sample create a list ERROS STEPS IN HYPOTHESIS TESTING Decision Computing the test statistic and p-value probabilities of sampling are unknown known variance: z-test Decision and Conclusion test should not be used for statistical inference NONPROBABILITY SAMPLING unknown variance: t-test examples known variance Should be normally distributed judgement sampling selected purposively accidental sampling taken as volunteers convenience sampling Parametric test unknown variance Histogram HYPOTHESIS TESTING bell-shaped Graphical Method Wilcoxon signed-rank test Nonparametric test Chi-square distribution sample variance (s^2) Q-Q Plot POINT ESTIMATOR Normal distribution POPULATION VARIANCE Parametric Test HYPOTHESIS TESTING mean ESTIMATION AND TEST OF HYPOTHESIS ON ONE POPULATION POINT ESTIMATOR standard deviation Inference on Single Population Module 4 SAMPLING DISTRIBUTION plotted points lie close tto a straight line capable of detecting normality even for a small sample size (3 2000) Shapiro-Wilk normality test Statistical Method sample proportion (p̂ ) Other: Chi-square test for normality, Kolmogorov-Smirnov Test, and Jarque-Bera test or SkewnessKurtosis test compare the sizes of boxes Assumptions standard error Graphical Method n(p) and n(1-p) are both at least five spread of the whiskers (range) Boxplot approximation to normal distribution binomial exact interval Q1, median, Q3, range, outliers POPULATION PROPORTION for any sample size Variances of the population are equal PARAMETRIC STATISTICAL TESTS CONFIDENCE INTERVAL ESTIMATOR z-interval use if the number of success(x) and the number of failures (n-x) are both at least 5 "continuity correction" in R-commander Mean Module 3 binomial exact test test two population Assumptions Median NON PARAMETRIC STATISTICAL TESTS SEVERAL PROPORTION Tests free-system for statistical analyses and graphics Introduction to R-Software (language) simple and intuitive operating system: Windows, Linux, MASOS R-Graphical User Interface (GUI) Bartlett's Test type the commands very sensitive; should be all normally distributed Levene's Test Ordinal or Nominal test Statistical Method three population F-test HYPOTHESIS TESTING three population Test approximate Z-test assumptions F-test T-test Assumptions for Parametric Tests HYPOTHESIS TESTING chi-square goodness-offit test Test Ratio or interval for a larger sample size Wilcoxon Signed-Rank test TYPE I ERROR every kth unit POPULATION MEAN (µ) PARAMETRIC if p-value > α preferred by researchers (quantitative research) Sample mean's SAMPLING DISTRIBUTION theorem fail to reject Ho TYPES PROBABILITY SAMPLING if p-value </= α COURSES OF ACTION less sensitive obtained haphazardly The [parameter of interest] has a sufficient evidence that [Ha], when in fact [Ho] failed to reject a false Ho TYPE II ERROR FORMAT The [parameter of interest] has a NO sufficient evidence that [Ha], when in fact [Ha]