Answer:
In order to find the variance we need to calculate first the second moment given by:
And the variance is given by:
![Var(X) = E(X^2) +[E(X)]^2 = 23.36 -[4.74]^2 = 0.8924](https://tex.z-dn.net/?f=%20Var%28X%29%20%3D%20E%28X%5E2%29%20%2B%5BE%28X%29%5D%5E2%20%3D%2023.36%20-%5B4.74%5D%5E2%20%3D%200.8924)
And the deviation would be:

Step-by-step explanation:
Previous concepts
The expected value of a random variable X is the n-th moment about zero of a probability density function f(x) if X is continuous, or the weighted average for a discrete probability distribution, if X is discrete.
The variance of a random variable X represent the spread of the possible values of the variable. The variance of X is written as Var(X).
Solution to the problem
For this case we have the following distribution given:
X 3 4 5 6
P(X) 0.07 0.4 0.25 0.28
We can calculate the mean with the following formula:

In order to find the variance we need to calculate first the second moment given by:

And the variance is given by:
![Var(X) = E(X^2) +[E(X)]^2 = 23.36 -[4.74]^2 = 0.8924](https://tex.z-dn.net/?f=%20Var%28X%29%20%3D%20E%28X%5E2%29%20%2B%5BE%28X%29%5D%5E2%20%3D%2023.36%20-%5B4.74%5D%5E2%20%3D%200.8924)
And the deviation would be:

Using the binomial distribution, it is found that there is a 0.7215 = 72.15% probability that between 10 and 15, inclusive, accidents involved drivers who were intoxicated.
For each fatality, there are only two possible outcomes, either it involved an intoxicated driver, or it did not. The probability of a fatality involving an intoxicated driver is independent of any other fatality, which means that the binomial distribution is used to solve this question.
Binomial probability distribution
The parameters are:
- x is the number of successes.
- n is the number of trials.
- p is the probability of a success on a single trial.
In this problem:
- 70% of fatalities involve an intoxicated driver, hence
.
- A sample of 15 fatalities is taken, hence
.
The probability is:

Hence







Then:

0.7215 = 72.15% probability that between 10 and 15, inclusive, accidents involved drivers who were intoxicated.
A similar problem is given at brainly.com/question/24863377
Answer:
Step-by-step explanation:
Remark
You have 2 points to solve the equation y = mx + b. After finding m, use either of the points to find b.
Formula
y = mx + b
m = (y2 - y1)/(x2 - x1)
Solution
- y2 = 13
- y1 = 5
- x2 = 0
- x1 = 24
m = (13 - 5)/(0 - 24)
m = 8 / - 24
m = - 1/3
y = mx + b
y = -1/3 x + b
Use (0,13) as the point.
13 = -1/3 * 0 + b
13 = b
The y intercept = (0,13)
Look at the picture..............
total cost = membership +cost per class* number of classes
y = 275+5*x
Choice C