Air travel on Mountain Airlines for the past $18$ weeks was:

$\backslash$table$[[$Week$,$Passengers$],[1,462],[2,463],[3,473],[4,476],[5,472],[6,478],[7,486],[8,481],[9,455],[10,499],[11,497],[12,505],[13,510],[14,497],[15,517],[16,517],[17,527],[18,530]]$

Use regression to develop a forecast for the expected number of passengers for the next three weeks. $($Round your answers to two decimal points.$)$

$\backslash$table$[[,],[$Week $19,],[$Week $20,],[$Week $21,]]$