Skip to main content
Back

Finding Residuals and Creating Residual Plots - Excel quiz

Control buttons has been changed to "navigation" mode.
1/15
  • What is the formula for calculating a residual in regression analysis?
    A residual is calculated as the actual y value minus the predicted y value (y - ŷ).
  • What is the regression line equation used in the example for predicting rider count?
    The regression line equation is y = -1.04x + 79.1.
  • What is the first step in creating a residual plot in Excel?
    The first step is to create a scatter plot of the original data.
  • How do you display the regression line equation on a scatter plot in Excel?
    You add a trend line, then check 'Display equation on chart' in the trend line options.
  • How do you calculate predicted y values (ŷ) in Excel using the regression equation?
    Plug each x value into the regression equation to compute the corresponding predicted y (ŷ).
  • What Excel feature allows you to quickly copy a formula to multiple cells?
    You can use the solid black cross at the cell's corner to click and drag the formula across cells.
  • What data do you need to create a residual plot in Excel?
    You need the explanatory variable (x) and the calculated residuals.
  • What does a residual plot with randomly scattered points near zero indicate?
    It indicates a good fit for the linear model and validates regression assumptions.
  • Why is it important to create a scatter plot before a residual plot?
    A scatter plot visually shows the relationship between variables and helps assess if a linear model is appropriate.
  • How do you calculate all residuals in Excel after finding predicted values?
    Subtract each predicted y (ŷ) from the actual y and copy the formula across all data points.
  • What should the title of your residual plot in Excel be?
    The title should be 'Residual Plot' to distinguish it from the original scatter plot.
  • Where is it helpful to place the residual plot relative to the original scatter plot?
    Place the residual plot below the original scatter plot to compare both visually.
  • What does it mean if residuals are both positive and negative and close to zero?
    It suggests the linear model fits the data well, with no systematic error.
  • What is the purpose of a residual plot in regression analysis?
    A residual plot helps validate the fit of the regression model and check for randomness in errors.
  • What should you do if you want more practice creating residual plots in Excel?
    You should check out additional examples and practice exercises provided in the lesson.