The cost of 10 days at Healthy Gym is $ .

Suppose that a college determines the following distribution for X = number of courses taken by a full-time student this semeste

lidiya [134]

Answer:

$E(X) = \sum_{i=1}^n X_i P(X_i) = 3*0.07 +4*0.4 +5*0.25 +6*0.28= 4.74$ In order to find the variance we need to calculate first the second moment given by:

$E(X^2) = \sum_{i=1}^n X^2_i P(X_i) = 3^2*0.07 +4^2*0.4 +5^2*0.25 +6^2*0.28= 23.36$ And the variance is given by:

$Var(X) = E(X^2) +[E(X)]^2 = 23.36 -[4.74]^2 = 0.8924$

And the deviation would be:

$Sd(X) =\sqrt{0.8924} =0.9447$

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:

$E(X) = \sum_{i=1}^n X_i P(X_i) = 3*0.07 +4*0.4 +5*0.25 +6*0.28= 4.74$

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

$E(X^2) = \sum_{i=1}^n X^2_i P(X_i) = 3^2*0.07 +4^2*0.4 +5^2*0.25 +6^2*0.28= 23.36$

And the variance is given by:

$Var(X) = E(X^2) +[E(X)]^2 = 23.36 -[4.74]^2 = 0.8924$

And the deviation would be:

$Sd(X) =\sqrt{0.8924} =0.9447$

3 0

3 years ago

Harry ate 5/8 of a sandwich

11111nata11111 [884]

Well do you know a common factor between 8, 5, and 12, if so it is super simple to find your answer. :)

4 0

4 years ago

Read 2 more answers

How is the product of two and -5 shown on a number line

tatuchka [14]

The correct answer is D

3 0

3 years ago

Read 2 more answers

Evan is going to the country fair this weekend. The admission to the fair is five dollars and the cost per ride is $.50. If his

Naya [18.7K]

Answer:

I believe he can go on 30 rides.

Step-by-step explanation:

The equation would be 5 + .5x = 20

Because $5 to get in, plus $.50 per ride (x is number of rides you are solving for), and $20 is total amount you can spend.

So, .5x=15 so x=30

6 0

4 years ago

For what value of x is PQ || BC?<br> A 5<br> B. 6<br> C. 7<br> D. 8

Dahasolnce [82]

Answer:

C. 7

Step-by-step explanation:

$In\: \triangle ABC\\\overline{PQ} \parallel \overline {BC}.. (given) \\$

Therefore, by Basic Proportionality theorem:

$\frac{AP}{PB} = \frac{AQ}{QC} \\\\\therefore \frac{x}{x+7} = \frac{x-3}{x+1} \\\\ \therefore \: \frac{x - x - 7}{x + 7} = \frac{x - 3 - x - 1}{x + 1} \\ (by \: dividendo) \\ \\ \frac{ - 7}{x + 7} = \frac{ - 4}{x + 1} \\ \\ \frac{7}{x + 7} = \frac{4}{x + 1} \\ \\ 7x + 7 = 4x + 28 \\ \\ 7x - 4x = 28 - 7 \\ \\ 3x = 21 \\ \\ x = \frac{21}{3} \\ \\ \huge \red{ \boxed{ x = 7}}$

5 0

3 years ago