STAT 210 Review Topics Basic Definitions/Terminology Descriptive Statistics Inferential Statistics Population Sample Variable Types of Data o Numeric o Categorical Methods for a Single Categorical Variable Simulation o Setting up spinner o Reading/interpreting the simulation graph o Estimating a p-value o Decision making Binomial Distribution o Conditions in context o Reading JMP output o Finding p-value o Decision making Confidence Interval o Why do we even use them? o Reading JMP output o Interpreting the interval o Decision making o Margin of error – what changes it, how the interval changes, etc. Goodness of Fit o Setting up hypotheses o Computing expected counts o Reading JMP output (Pearson Chi-square Test) Test statistic P-value o Conclusion in context 1 Methods for Two Categorical Variables Case 1: H0: p1 ≤ p2 Ha: p1 > p2 OR H0: p1 ≥ p2 Ha: p1 < p2 o Fisher’s Exact Test – no test statistic, p-value from bottom of JMP output Case 2: H0: p1 = p2 Ha: p1 ≠ p2 o Chi-square Test – if at least 3 expected counts are 5 or more expected counts, test statistic, p-value from Pearson part of JMP output. o Fisher’s Exact Test – if 2 or more expected counts are less than 5 Relative Risk o Interpreting mosaic plot o Reading JMP output o Interpreting the relative risk o When does an association/difference exist? Odds Ratio o Interpreting mosaic plot o Reading JMP output o Interpreting the odds ratio o When does an association/difference exist? Confidence Interval for p1 – p2 o Need 3 things – estimate ( pˆ 1 pˆ 2 ), quantile, standard deviation (standard error) o Interpreting the interval o Conclusions based upon interval R x C Tables o Interpreting mosaic plot o Hypotheses o Computing expected counts o Reading JMP output – test statistic, p-value Mosaic Plots o What they look like if no relationship o What they look like if there is a relationship Methods for a Single Numeric Variable Descriptive Statistics o Numerical – mean, standard deviation, variance, Five Number Summary, IQR, Range, skewness, kurtosis o Graphical – identifying shape, outliers, standard deviation comparisons Data Concentration/Outliers o Z-scores o Empirical Rule o Chebyshev’s Rule Sampling Distribution for the Sample Mean o Center, shape, variability o Central Limit Theorem 2 Hypothesis Test o Setting up hypotheses o Conditions/assumptions – n is sufficiently large (≥30) or normal distribution o Reading JMP output – p-value, graphs o Computing test statistic o Finding p-value o Conclusion in context o Wilcoxon Signed Rank Test – when n < 30 and not normal, but SYMMETRIC o Being able to describe in context a Type I Error and Type II Error and consequences/implications Type I and Type II Errors o Type I – Have evidence for RQ (Reject H0) when H0 is true o Type II – No evidence for RQ (Do not reject H0) when H0 is false o Consequences/implications of making either error Confidence Interval o Reading JMP output o Interpreting the interval o Decision making Methods for a Single Numeric Variable across Two Groups Dependent vs. Independent Samples Dependent Samples o Use µd in hypotheses o Assumptions/conditions – npairs ≥ 30 or differences normal o Computing test statistic o Reading JMP output o Finding p-value o Conclusion in context Independent Samples o Use µ1 and µ2 in hypotheses o Assumptions/conditions – both n1 and n2 ≥ 30, or both populations normal, Equal variances o Reading JMP output o Computing test statistic o Finding p-value o Conclusion in context Confidence Intervals o Reading JMP output o Interpreting the interval o Decision making 3 Methods for a Single Numeric Variable across More than Two Groups When is ANOVA used? Hypotheses Assumptions/conditions – equal variances, normality, independent Reading JMP output Finding test statistic and p-value Conclusion in context Methods for Two Numeric Variables Correlation o Measures strength and direction of linear relationship o Between -1 and 1 o Strongest linear relationships at +1 and -1 o No linear relationship around 0 o Square root of R2 Simple Linear Regression o Estimated equation from JMP output o Interpreting slope o Interpreting intercept o Predicting 4