What are the names of the three built-in classes of numbers? What function would you call to find out the number of levels of a factor? How might you convert the string “ XXXXXXXXXX” to a number? Name...

What are the names of the three built-in classes of numbers?

What function would you call to find out the number of levels of a factor?

How might you convert the string “6.283185” to a number?

Name at least three functions for inspecting the contents of a variable.