Consider the analysis in Computer Exercise C11 in Chapter 4 using the data in HTV, where educ is the dependent variable in a regression.

(i) How many different values are taken on by educ in the sample? Does educ have a continuous distribution?

(ii) Plot a histogram of educ with a normal distribution overlay. Does the distribution of educ appear anything close to normal?

(iii) Which of the CLM assumptions seems clearly violated in the model

educ = β₀ + β₁motheduc + β₂fatheduc + β₃abil + β₄abil² + u?

How does this violation change the statistical inference procedures carried out in Computer Exercise C11 in Chapter 4?