The scatterplot and the model in Fig. 81 describe the association between the percentage of children who receive free or reduced-fee lunches at school and the percentage of people who wear bicycle helmets, for each of 12 neighborhoods.

A residual plot is shown in Fig. 82.

a. The researchers determined that the data point for the neighborhood Los Arboles, California, is an outlier. Describe the values of the variables for that neighborhood.
b. If an organization wants to encourage the use of bicycle helmets in low-income neighborhoods, why might it be useful to perform additional research about Los Arboles?
c. Figure 83 shows as catterplot and the regression model after removing the outlier. Is the outlier an influential point? Explain.
d. Is the vertical spread of the residual plot about the same for each value of the explanatory variable? Should the model be used to make predictions? Explain.

Reduced-Fee Lunch versus Helmet 60 40 30 20 10 10 20 30 40 50 60 70 80 90 Percent receiving free or reduced-fee lunch Reduced-Fee Lunch versus Residual S 20 10 -10 0 10 20 30 40 50 60 70 80 90 Percent receiving free or reduced-fee lunch