Airbnb has collected data on the number of users registered on its website. Past number of users and forecast data are shown in the table. Show all work.

a$)$ Please calculate the $E_t$

b$)$ Please calculate the CFE

c$)$ Please calculate the $\frac{?}{\text{b}\text{a}\text{r}}(E)$

d$)$ Please calculate the MSE

e$)$ Please calculate the standard deviation of errors $$

f$)$ Please calculate the MAD

g$)$ Please calculate the MAPE