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3 years ago

Which statement about the data is true

Mathematics

1 answer:

Alina [70]3 years ago

7 0

Answer:

D. A value of 0.9 is more than 2 standard deviations from the mean.

Step-by-step explanation:

A is wrong, because the standard deviation is +/-0.15 (the measure up or down from the mean)

B is wrong, because the mean is exactly 0.5

C is wrong, because 1 standard deviation up from the mean is 0.65, and 0.7 is outside of that.

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For what values of x is x2-36=5x true?

katrin2010 [14]

Answer:

x=-12

Step-by-step explanation:

x2-36=5x

add 36 to both sides

x2=5x+36

subtract 5x from both sides

x(-3)=36

divide both sides by -3

x=-12

substitute to prove right

(-12)2-36=5(-12)

-24-36=-60

-60=-60

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Answer:

13. y=2x+24

14. 1.5x+24

Step-by-step explanation:

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3 years ago

Someone help its math 50 points

dimaraw [331]

Answer:

i think it is (-1,0)

Step-by-step explanation:

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2 years ago

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Let $\mu$ and $\sigma^2$ denote the mean and variance of the random variable x. determine $e[(x-\mu)/\sigma]$ and $e{[((x-\mu)/\

Nezavi [6.7K]

$\mathbb E\left(\dfrac{X-\mu}{\sigma}\right)=\dfrac1\sigma\mathbb E(X)-\dfrac\mu\sigma=\dfrac{\mu-\mu}\sigma=0$

$\mathbb E\bigg(\left(\dfrac{X-\mu}\sigma\right)^2\bigg)=\dfrac1{\sigma^2}\mathbb E\left(X^2-2\mu X+\mu^2\right)=\dfrac{\mathbb E(X^2)-2\mu\mathbb E(X)+\mu^2}{\sigma^2}$
$=\dfrac{\mathbb E(X^2)-2\mu^2+\mu^2}{\sigma^2}=\dfrac{\mathbb E(X^2)-\mu^2}{\sigma^2}=\dfrac{\mathbb E(X^2)-\mathbb E(X)^2}{\sigma^2}$
$=\dfrac{\mathbb V(X)}{\sigma^2}=\dfrac{\sigma^2}{\sigma^2}=1$

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4 years ago

In answering on a multiple choice test, a student either know the answer or guesses. Let p be the probability that the students

LenaWriter [7]

Answer:

$P(A_{1}|B ) =\frac{mp}{1+p(m-1)}$

Step-by-step explanation:

For mutually exclusive events as A1, A2, A3, etc, Bayes' theorem states:

$P(A|B)= \frac{P(B|A)P(A)}{P(B)}$

P(A|B) is a conditional probability: the likelihood of event A occurring given that B is true.

P(B|A) is a conditional probability: the likelihood of event B occurring given that A is true.

P(A) is the probability that A occurs

P(B) is the probability that B occurs

For this problem:

A1 is the probability that the student knows the answer

A2 is the probability that the student guesses the answer

B is the probability that the student answer correctly

$P(A_{1})=p \\P(A_{2})=1-p \\P(B|A_{1})=1 \\P(B|A_{2})=\frac{1}{m} \\P(B)= P(A_{1})P(B|A_{1}) + P(A_{2})P(B|A_{2})= p+\frac{1-p}{m} \\$

P(B|A₁) means the probability that the answer is correct when he knew the answer

P(B|A₂) means the probability that the answer is correct when he guessed the answer

P(A₁|B) means the probability that he knew the answer when the answer was correct

Replacing everything in the Bayes' theorem you get:

$P(A_{1}|B)= \frac{P(B|A_{1})P(A_{1})}{P(B)}=\frac{(1)(p)}{p+\frac{1-p}{m}} =\frac{mp}{mp+1-p} =\frac{mp}{1+p(m-1)}$

5 0

3 years ago