Problem 4. Suppose for this problem you work as a personal accountant. One of your clients invested $12,000 from their retirement account into a stable index fund. The value of this investment over the last 18 years is tracked in the Problem 3 tab of Excel. a) (In Excel, 2 points) Build a scatter-plot of the account value vs. year after 2005. Be sure to title your graph and label your axes. Additionally, change the scale on the y-axis to start at 4000 to avoid a squished graph.

b) (1 point) Your client wants to know the percentage gain in the value of the account per year. Briefly explain why using an exponential function for regression on this data would be the best type of function to use to help answer this question. c) (in Excel, 2 points) Have Excel add an exponential trendline to your scatterplot; be sure to display the equation and R2 values. d) (2 points) What is the predicted value of the account in 2026? You must include a calculation based on what you found in part c) that supports your answer. e) (1 point) Is your calculation from the previous part an interpolation or extrapolation? f ) (2 points) At what percentage per year does our trendline estimate the account is increasing? Include a calculation that supports your answer.