A car dealership sells two types of vehicles:
- $60\%$ are fully electric vehicles;
- $40\%$ are rechargeable hybrid vehicles.
$75\%$ of buyers of fully electric vehicles and $52\%$ of buyers of rechargeable hybrid vehicles have the material possibility of installing a charging station at home.
A buyer is chosen at random and the following events are considered:
- $E$: ``the buyer chooses a fully electric vehicle'';
- $B$: ``the buyer has the possibility of installing a charging station at home''.
Throughout the exercise, probabilities should be rounded to the nearest thousandth if necessary.
- Calculate the probability that the buyer chooses a fully electric vehicle and has the possibility of installing a charging station at home.
A weighted tree diagram may be used. - Prove that $P(B) = 0.658$.
- A buyer has the possibility of installing a charging station at home. What is the probability that he chooses a fully electric vehicle?
- A sample of 20 buyers is chosen. This sampling is treated as drawing with replacement. Let $X$ be the random variable that gives the total number of buyers able to install a charging station at home among the sample of 20 buyers. a. Determine the nature and parameters of the probability distribution followed by $X$. b. Calculate $P(X = 8)$. c. Calculate the probability that at least 10 buyers can install a charging station. d. Calculate the expected value of $X$. e. The dealership manager decides to offer the installation of the charging station to buyers who have the possibility of installing one at home. This installation costs $1200$~\euro. On average, what amount should she plan to spend on this offer when selling 20 vehicles?