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2 years ago

The following data set represents the number of siblings 6students have in much class

Mathematics

2 answers:

Hitman42 [59]2 years ago

8 0

There is nothing there

yuradex [85]2 years ago

3 0

Answer:

there is nothing there

Step-by-step explanation:

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Jack leaves school to go home, He walks 6 blocks North and then 8

inysia [295]

Jack is 10 blocks away from the school

3 0

2 years ago

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

What is expanded number 289 mean

natita [175]

200
80 thats the answer
9

4 0

3 years ago

75% of n is 45. n is what percent of 90?

Law Incorporation [45]

Answer:

66.67%

Step-by-step explanation:

75 /100 = .75

.75n = 45

45/.75 = 60

60 is n

60/90 = .666667

.666667 * 100 = 66.67%

3 0

2 years ago

Read 2 more answers

This is to help my wonderful mother. What is 1/3rd of 4 1/2s and 8 1/4s?

crimeas [40]

4 1/2 = 9/2
8 1/4 = 33/4

1/3 x 9/2 = 3/2
1/3 x 33/4 = 33/12

5 0

3 years ago