Please answer this correcttly, I will give brainliest if it is correct and you get 13 points

In a recent year, Washington State public school students taking a mathematics assessment test had a mean score of 276.1 and a s

Oksi-84 [34.3K]

Answer:

a) $\mu_{\bar x} =\mu = 276.1$

$\sigma_{\bar x} =\frac{\sigma}{\sqrt{n}}=\frac{34.4}{\sqrt{64}}=4.3$

b) From the central limit theorem we know that the distribution for the sample mean $\bar X$ is given by:

$\bar X \sim N(\mu=276.1, \frac{\sigma}{\sqrt{n}}=4.3)$

c) $P(\bar X \geq 285)=P(Z\geq \frac{285-276.1}{4.3}=2.070)$

$P(Z\geq2.070)=1-P(Z$

Step-by-step explanation:

Let X the random variable the represent the scores for the test analyzed. We know that:

$\mu=E(X) = 276.1 , \sigma=Sd(X) = 34.4$

And we select a sample size of 64.

The central limit theorem states that "if we have a population with mean μ and standard deviation σ and take sufficiently large random samples from the population with replacement, then the distribution of the sample means will be approximately normally distributed. This will hold true regardless of whether the source population is normal or skewed, provided the sample size is sufficiently large".

Part a

For this case the mean and standard error for the sample mean would be given by:

$\mu_{\bar x} =\mu = 276.1$

$\sigma_{\bar x} =\frac{\sigma}{\sqrt{n}}=\frac{34.4}{\sqrt{64}}=4.3$

Part b

From the central limit theorem we know that the distribution for the sample mean $\bar X$ is given by:

$\bar X \sim N(\mu=276.1, \frac{\sigma}{\sqrt{n}}=4.3)$

Part c

For this case we want this probability:

$P(\bar X \geq 285)$

And we can use the z score defined as:

$z=\frac{\bar x -\mu}{\sigma_{\bar x}}$

And using this we got:

$P(\bar X \geq 285)=P(Z\geq \frac{285-276.1}{4.3}=2.070)$

And using a calculator, excel or the normal standard table we have that:

$P(Z\geq2.070)=1-P(Z$

8 0

3 years ago

SOLVE FOR BRAINLIEST!

marissa [1.9K]

I think it would be the second question!

7 0

2 years ago

Giving brainlist to whoever answers

Setler79 [48]

Answer:

m<A=94

Step-by-step explanation:

(2x+10)+(2x+2)=180

4x+12=180

-12 -12

4x=168

/4 /4

x=42

m<A= 2x+10

m<A=2(42)+10

m<A=84+10

m<A=94

Check:

Add m<A and m<B which should equal 180.

m<B=2x+2

m<B=2(42)+2

m<B=84+2

m<B=86

94+86=180

3 0

2 years ago

-9 more than a number results in -20

damaskus [11]

Answer:

-9+x=-20

Step-by-step explanation:

I am not so positive on this one, but if you are not doing inequalities, then this should be correct.

"More than" would insinuate that you are adding. In this class, you would have a number to replace that x, but since no number was given, you place the x in its place. x=-11, because when you "add" -9 with something to get -20, it would have to be -11. Negative numbers can be confusing because when you subtract a negative number by another negative, you end up with a negative. Like in this case. Normally, you would just put -11, so it would look like -9 - 11 = -20. But since this says "more than", unless you are doing inequalities, you add.

If you are doing inequalities, then your answer should be this:

-9 > x = -20

I hope this helps!

-No one

4 0

2 years ago

A rectangular flower garden in Samantha's backyard has 100feet around its edge .the width of the garden is 20 feet what is the.

ddd [48]

I don't understand the question. please rephrase

4 0

2 years ago

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