a. Do some firms match contributions at higher than a dollar for dollar rate?
b. Is there a concentration of firms with 100 percent participation rates?
c. What fraction of the variation in participation rates is explained by the match rate?
d. What is the expected change in participation rate if a firm increases its match rate by two percentage points.
e. do the residuals follow a symmetric distribution?
f. Do these residual display the properties that we assumed for our regression model?