I only need help with $3$a and $3$b pleade and thank you

DataSpan, Inc., automated its plant at the start of the current year and installed a flexible manufacturing system. The company is also evaluating its suppliers and moving toward Lean Production. Many adjustment problems have been encountered, including problems relating to performance measurement. After much study, the company has decided to use the performance measures below, and it has gathered data relating to these measures for the first four months of operations.

$\backslash$table$[[$Month$],[$Throughput time $($days$),1,2,3,4],[$Delivery cycle time $($days$),?,?,?,?$