Your regression of 41 observations and 5 regressors shows adjusted R2 =0.24. What is the value of R?

Supposed we include X1 in our single regression € Y = β0 + β1X1 + u , but we leave out X2, a variable that is negatively correlated with the included variable X1. X2 is a determinant of Y (the dependent variable), and the effect of X2 on Y is positive. The effect of X1 on Y is negative. What is the consequence of leaving X2 out of the model?

Suppose 30% of the population of working people in a country have a high school degree or less. If the average annual earnings for that group is $35,000 and the average earnings per year for the more educated group of people (people with more than a high school diploma) is $70,000, then you can say that the average annual earnings for the working population of the country is