The article Drift in Posturography Systems Equipped with a Piezoelectric Force Platform: Analysis and Numerical Compensation (L. Quagliarella, N. Sasanelli, and V. Monaco, IEEE Transactions on Instrumentation and Measurement, 2008:9971004) reported the results of an experiment to determine the effect of load on the drift in signals derived from a piezoelectric force plate. The correlation coefficient y between output and time was computed for various loads x in kN, as shown in the following table. x y 0.196 0.9710 0.245 0.9735 0.294 0.9694 0.343 0.9684 0.392 0.9624 0.441 0.9688 0.490 0.9519 0.539 0.9573 0.588 0.9515 a. Compute the least-squares line for predicting y from x. b. Plot the residuals versus the fitted values. Does the least-squares line seem appropriate? c. Compute the least-squares line for predicting y from x 2 . d. Plot the residuals versus the fitted values. Does the least-squares line seem appropriate? e. For each model, find a 95% confidence interval for the mean value of y when x = 0.32. Are the confidence intervals similar?

BoxPlot is a way to show 5 number summary. The actual boxcovers the middle 50% of data (from Q1 to Q3) Multiple box plots are used to make comparisons. DotPlot are used to display 5 number summary as well. It is generally used for smaller data because a dot is used for each individual value. Where do outliars come from Human error, data entered wrong Improper values, ex. Weight can be lb or kg Could be a correct respond but just not fit in Use the IQR x 1.5 to find suspected outliers Relative Frequency Interpretation When doing a large number of trials, this is the probablitiy of an outcome as the proportion of times it would occur over the many trials. Ex. Flipping a coin Personal Interpretations Personal or subjective probability is the d