Question: An experiment was conducted to determine the effect of practice time (in seconds) on the percent of unfamiliar words recalled. Here is a Fathom scatterplot of the results with a least-squares regression line superimposed.
(a) Sketch a residual plot. Be sure to label your axes.
(b) Explain why a linear model is not appropriate for describing the relationship between practice time and percent of words recalled.
(c) We used Fathom to transform the data in hopes of achieving linearity. The screen shots on the right show the results of two different transformations. Would an exponential model or a power model describe the relationship better? Justify your answer.
(d) Use each model to predict the word recall for 25 seconds of practice. Show your work. Which prediction do you think will be better?