For each of the following models, indicate whether it is a linear re$-$

gression model, an intrinsically linear regression model, or neither of

these. In the case of an intrinsically linear model, state how it can be

expressed in the form of Yi $=\backslash$beta $0+\backslash$beta $1$X$1$i $+\backslash$beta $2$X$2$i $+...+\backslash$beta kXki $+$i by

a suitable transformation.

$($a$)$ Yi $=\backslash$beta $0+\backslash$beta $1$X$1$i $+\backslash$beta $2$ log X$2$i $+\backslash$beta $3$X$2$

$1$i $+$i

$($b$)$ Yi $=$i exp$(\backslash$beta $0+\backslash$beta $1$X$1$i $+\backslash$beta $2$X$2$

$2$i$)$

$($c$)$ Yi $=\backslash$beta $0+$ log$(\backslash$beta $1$X$1$i$)+\backslash$beta $2$X$2$i $+$i