The ages of the people who attend a weekly yoga class at the local yoga studio are shown in the table below.

Consider a discrete random variable x with pmf px (1) = c 3 ; px (2) = c 6 ; px (5) = c 3 and 0 otherwise, where c is a positive

PtichkaEL [24]

Looks like the PMF is supposed to be

$\mathbb P(X=x)=\begin{cases}\dfrac c3&\text{for }x\in\{1,5\}\\\\\dfrac c6&\text{for }x=2\\\\0&\text{otherwise}\end{cases}$

which is kinda weird, but it's not entirely clear what you meant...

Anyway, assuming the PMF above, for this to be a valid PMF, we need the probabilities of all events to sum to 1:

$\displaystyle\sum_{x\in\{1,2,5\}}\mathbb P(X=x)=\dfrac c3+\dfrac c6+\dfrac c3=\dfrac{5c}6=1\implies c=\dfrac65$

Next,

$\mathbb P(X>2)=\mathbb P(X=5)=\dfrac c3=\dfrac25$

$\mathbb E(X)=\displaystyle\sum_{x\in\{1,2,5\}}x\,\mathbb P(X=x)=\dfrac c3+\dfrac{2c}6+\dfrac{5c}3=\dfrac{7c}3=\dfrac{14}5$

$\mathbb V(X)=\mathbb E\bigg((X-\mathbb E(X))^2\bigg)=\mathbb E(X^2)-\mathbb E(X)^2$
$\mathbb E(X^2)=\displaystyle\sum_{x\in\{1,2,5\}}x^2\,\mathbb P(X=x)=\dfrac c3+\dfrac{4c}6+\dfrac{25c}3=\dfrac{28c}3=\dfrac{56}5$
$\implies\mathbb V(X)=\dfrac{56}5-\left(\dfrac{14}5\right)^2=\dfrac{84}{25}$

If $Y=X^2+1$ , then $X^2=Y-1\implies X=\sqrt{Y-1}$ , where we take the positive root because we know $X$ can only take on positive values, namely 1, 2, and 5. Correspondingly, we know that $Y$ can take on the values $1^2+1=2$ , $2^2+1=5$ , and $5^2+1=26$ . At these values of $Y$ , we would have the same probability as we did for the respective value of $X$ . That is,

$\mathbb P(Y=y)=\begin{cases}\dfrac c3&\text{for }y=2\\\\\dfrac c6&\text{for }y=5\\\\\dfrac c3&\text{for }y=26\\\\0&\text{otherwise}\end{cases}$

Part (5) is incomplete, so I'll stop here.

8 0

3 years ago

23, A right triangle is inscribed in a circle of radius 9. The length of the hypotenuse of the right

aivan3 [116]

Answer:

18

Step-by-step explanation:

5 0

3 years ago

R is the interior of angle TUV. The measure of RUV=30degrees, the measure of TUV=3x+16, and the measure of TUR=x+10. Find x and

choli [55]

Given

R is the interior of ∠ TUV.

m∠ RUV=30degrees, m∠ TUV=3x+16, and m∠ TUR=x+10.

Find the value of x and the m ∠TUV.

To proof

As given in the question

m ∠TUV=3x+16, and m ∠TUR=x+10

thus

m∠ RUV = m∠ TUV - m∠ TUR

= 3x + 16 - x -10

= 2x + 6

As given

m ∠RUV=30°

compare both the values

we get

30 = 2x + 6

24 = 2x

12 = x

put this value in the m ∠TUV= 3x+16

m ∠TUV= 12× 3 +16

= 52°

Hence proved

7 0

2 years ago

A customer buys 15.5 cheese pizzas which are $10.50 each. What is the total? Round it to the nearest hundredth.

Cerrena [4.2K]

First of all, how do you buy exactly 15.5 pizzas?
what is a 0.5 pizza?

anyway

cost=cost per pizza times number of pizzas
cost per pizza=10.50
number of pizzas=15.5

cost=10.50 times 15.5
cost=162.75

total cost is $162.75

5 0

3 years ago

AEFG is located at E (0,0), F (-7, 4), and G (0,8). Which statement correctly classifies AEFG?

viva [34]

Answer:

ΔEFG is an isosceles triangle

Step-by-step explanation:

8 0

3 years ago