91影视

The values for counts of drivers are tabulated under different categories.

The addition rule is defined as:

$P\left(A\text{or}B\right)=P\left(A\right)+P\left(B\right)-P\left(A\text{and}B\right)$

It computes the probability of occurrence of event A or B using the probability of A, B and their joint occurrence.

Add all values in the rows and columns and note under totals.

Define the events as follows:

E: The randomly selected driver did not use a seatbelt.

F: The randomly selected driver was not killed.

The number of drivers whodid not use seatbelts is 7442.

The number of drivers who were notkilled is 10045.

The number of drivers who were neither killed nor used seatbelts is 3040.

The total number of drivers surveyed is 18102.

The probabilities are computed as:

$$\begin{gathered} P\left(E\right)=\frac{7442}{18102} \\ P\left(F\right)=\frac{10045}{18102} \\ P\left(E\text{and}F\right)=\frac{3040}{18102} \end{gathered}$$

The probability that a randomly selected driver was neither killed nor used a seatbelt is:

$$\begin{gathered} P\left(E\text{or}F\right)=P\left(E\right)+P\left(F\right)-P\left(E\text{and}F\right) \\ =\frac{7442}{18102}+\frac{10045}{18102}-\frac{3040}{18102} \\ =0.798 \end{gathered}$$

Thus, the probability that a randomly selected driver was neither killed nor used seatbelts is 0.798.