C784 Statistics Full Course Review Questions & Answers

Lurking Variable - ANSWERSAssociated with the explanatory and the response variables that is not directly being studied. Simpson's Paradox - ANSWERSOccurs when a trend or result that appears in groups of data disappears when we combine the data. Regression Analysis - ANSWERSA process for estimating and analyzing the relationship between variables. Least-Squares Regression Line - ANSWERSAKA the line of best fit. y = mx + b "rise over run" Interpolation - ANSWERSUsing existing data along with the Least-Squares Regression Line to make a prediction. Extrapolation - ANSWERSEstimation by projecting OUTSIDE known data points. p-value - ANSWERSthe probability that a result occurred by chance Significance Levels in Hypothesis Testing - ANSWERSStatistically Significant: If a measured p-value is less than the significance level. NOT Statistically Significant: If a measured p-value is MORE than the significance level. Empirical Rule - ANSWERS68 - 95 - 99.7 68% is w/in 1 standard deviation of the mean 95% is w/in 1 standard deviation of the mean 99.7% is w/in 1 standard deviation of the mean Used for Categorical (Qual) Data - ANSWERSBar Chart Pie Chart Mean - ANSWERSAverage - adding series then dividing by the total number in that series Center & Spread Measures - ANSWERSSYMMETRIC - Mean (center) / Standard Deviation (spread) SKEWED - Median (center) / IQR (spread) CATEGORICAL - Mode (center) / no spread What is the difference between a bar chart and a histogram? - ANSWERSBAR CHART - Categorical data distributed over groups of categories HISTOGRAM - Quantitative data distributed over various intervals Outlier Formula - ANSWERS1.5 x IQR above Q3 or below Q1 Graphical Displays for Quantitative Variables - ANSWERSHISTOGRAMS - large data sets STEM PLOTS - keeps individual data points DOT PLOTS - smaller data sets BOX PLOTS - center, spread and 5 number summary SCATTER PLOTS - x,y axis 5 Number Summary - ANSWERSMin - Q1 - Median - Q3 - Max Graphical Displays and Corresponding Numerical Analysis Tools for Examining Data Relationships - ANSWERSC C - Two-way Frequency Tables (aka Contingency Table) use conditional percentages and relative frequencies C Q - Side-by-Side Boxplots use 5 number summaries Q Q - Scatterplots use correlation coefficients InterQuartile Range (IQR) - ANSWERSQ3-Q1 Standard Deviation - ANSWERSAverage distance each data point is from the mean 3 Types of Percentages on a Two-Way Frequency Table - ANSWERSOVERALL% - (aka Relative Frequencies) When all of the counts are divided by the overall total CONDITIONAL ROW% - when the explanatory variable is in rows; calculated by dividing the joint frequencies of each row by the row total CONDITIONAL COLUMN% - when the explanatory variable is in the columns; calculated by dividing joint frequencies of each column by column total