$1.$ Write a simple linear regression line $($equation$).$ Define Y$,$ a$,$ b$,$ and x $($t$).$

$2.$ Define r$,$ r squared, and adjusted r

$3.$ Define MAD, MSE, MAPE, why these are important?

$4.$ Among other services and products that Karl's Copiers provides, it sells and repairs photocopy machines. It is now the end of December, $2021$ and the manager needs to plan his service staffing for January, $2022.$ The manager first needs to forecast the number of service calls for January, $2022.$ Following are the record of service calls for the past $12$ months

Month Number of Service Calls Month Number of Service Calls

January $30$ July $31$

February $24$ August $38$

March $27$ September $37$

April $31$ October $36$

May $37$ November $32$

June $34$ December $29$