Lecture 7Outline of Last Lecture I. Frequency DistributionII. Making Frequency TablesIII. Reading HistogramsIV. Different types of plots (frequency polygon, dot plot, stem-and-leaf plot, pareto chart, pie chart, scatter plot, box plot, time-series graph, other)V. Misuses of Statistics and Misleading GraphsVI. Experimental Research (variables and correlation)Outline of Current Lecture VII. CorrelationCurrent Lecture- Correlation: A correlation is a relationship between two variables; can be generated for predicting the value of one variable given the value of the other variable; This is appropriate for sample data that come in pairs- Correlation Researcho investigates a linear relationship between two variableso Variables must be continuouso Data can be presented graphically (scatter plot)o Neither variable is truly the independent or dependent variableo Called a bivariate relationshipo There is no causationo Positive correlation- indicates that when X increases, so does Yo Negative correlation- indicates that when X increases, Y decreases (and vice versa)- Linear correlation coefficient (r): a numerical measure of the strength of the relationship between two variables representing quantitative datao Requirements: The sample of paired (x, y) data is a random sample of independent quantitative data Visual examination of the scatterplot must confirm that the points approximate a straight-line pattern The outliers must be removed if they are known to be errors. The effects ofany other outliers should be considered by calculating r with and without the outliers included- The coefficient of determination (r2): the proportion of the variation in y that is explained by the linear relationship between x and yKIN 4310- Common errors involving correlationo Causation- It is wrong to conclude that correlation implies causalityo Averages- Averages suppress individual variation and may inflate the correlationcoefficiento Linearity- There may be some relationship between x and y even when there is no linear correlation- Excel Functiono =CORREL(array1,array2)These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used asa supplement to your own notes, not as a