Approximately how long would it take an investment that is compounded annually to triple at an interest rate of 6%?

In the game of roulette, a wheel consists of 38 slots numbered 0, 00, 1, 2,..., 36. To play the game, a metal ball is spun a

Oxana [17]

Answer:

$E(X)=-0.0526$

$Sd(X)=5.763$

Step-by-step explanation:

In statistics and probability analysis, the expected value "is calculated by multiplying each of the possible outcomes by the likelihood each outcome will occur and then summing all of those values".

The variance of a random variable Var(X) is the expected value of the squared deviation from the mean of X, E(X).

And the standard deviation of a random variable X is just the square root of the variance.

Let X be a random variable which denotes the money you may win or lose on each spin.

In the game of roulette, a wheel consists of 38 slots. To play the game, a metal ball is spun around the wheel and is allowed to fall into one of the numbered slots. If the number of the slot the ball falls into matches the number you selected, we win $35; otherwise we lose $1. So we have just one possibility to win and 37 of lose on an individual game.

___________________________

X P(X)

___________________________

35 1/38

-1 37/38

___________________________

In order to calculate the expected value we can use the following formula:

$E(X)=\sum_{i=1}^n X_i P(X_i)$

And if we use the values obtained we got:

$E(X)=(35)*(\frac{1}{38})+(-1)(\frac{37}{38})=-0.0526$

In order to find the standard deviation we need to find first the second moment, given by :

$E(X^2)=\sum_{i=1}^n X^2_i P(X_i)$

And using the formula we got:

$E(X^2)=(35^2)*(\frac{1}{38})+((-1)^2)(\frac{37}{38})=33.211$

Then we can find the variance with the following formula:

$Var(X)=E(X^2)-[E(X)]^2 =33.211-(-0.0526)^2 =33.208$

And then the standard deviation would be given by:

$Sd(X)=\sqrt{Var(X)}=\sqrt{33.208}=5.763$

4 0

2 years ago

For a segment of a radio show a disc jockey can play 10 records. If there are 12 records to select from in how many ways can the

sveta [45]

Answer:

<h2>66 different ways </h2>

Step-by-step explanation:

This is a combination question. Combination has to do with selection. For example if r objects are to be selected from n pool of oblects, this can be done in nCr number of ways.

nCr = n!/(n-r)r!

According to the question, if a radio show can only play 10 records out of 12 records available, this can be done in 12C10 number of ways.

12C10 = 12!/(12-10)!10!

= 12!/2!10!

= 12*11*10!/2*10!

= 12*11/2

= 6*11

= 66 different ways

7 0

2 years ago

Alina has 15x + 12 yards of ribbon. She uses 6x - 3 yards for a project. How many yards does she have left?

Andrews [41]

Answer:

-1.66666666667 yards

Step-by-step explanation:

15x+12=6x-3

subtract 6x on both sides

9x+12=-3

subtract 12 on both sides

9x=-15

x=-1.6666666666667

8 0

2 years ago

I need help with this problem please! It's very confusing to me.

Daniel [21]

2.25X5= 11.25

2 1/4 turns into 2.25 as a decimal, and a pentagon has 5 equal sides, so you take 2.25 and multiply it by 5 to get your answer

11.25ft

4 0

3 years ago

What is the table of values for y=x+2

Marta_Voda [28]

Answer:

x y

-2 0

0 2

Slope: 1

y-intercept = 2 ( 0, 2 )

Hope this helped!

Have a supercalifragilisticexpialidocious day!

8 0

2 years ago