Interpret the coefficient of age in the simple regression with a dependent variable weeks and an independent variable age: As workers get older, for each additional year $,$ the time a manufacturing worker has been without a job increases with one and one half weeks $.$ As workers get older $,$ for each additional year $,$ the time a manufacturing worker has been without a job increases with one and one half weeks $,$ if everything else remains constant $.$ For each additional week without a job $,$ the time a manufacturing worker has been jobless increases with one and one half weeks $,$ if everything else remains constant $.$ For each additional one and one half weeks without a job $,$ the time a manufacturing worker has been jobless increases with one week $.$