CK Code: ch2-21a It might be helpful to get an average finger length by adding up all the values of Thumb, Index, Middle, Ring, and Pinkie and dividing by 5. Write code for adding the variable AvgFinger to Fingers that does this. Write code to look at the first few lines of the Fingers data frame as well, so you can check that your calculations look correct. I Write code to create this summary variable Fingers$AvgFinger