Consider the following exponential probability density function. $$ f(x)=\frac{1}{3} e^{-\frac{x}{3}} \quad \text { for } \quad x \geq 0 $$ a. Which of the following is the formula for $P\left( \leq x_{0} ight) ?$ $1 \quad P\left(x \leq x_{0} ight)=e^{- \frac{x_{0}}{3}}$ $2 \quad Plleft(x \leq x_{0} ight)=1-e^{-\frac{x_{0}}{3}}$ $3 P\left(x \leq x_{0} ight)=1-e^{-x_{0}}$ $-$ Select your answer - $v$ b. Find $P(x \leq 1$ (to 4 decimals) C. Find $P(x \geq 3) $ (to 4 decimals). d. Find $P(x \leq 5) $ (to 4 decimals). e. Find $P(1 \leq x \leq 5$ (to 4 decimals). SP.SS.390 X