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3 years ago

Helpppp please anyone. I don't understand

Mathematics

1 answer:

vovikov84 [41]3 years ago

7 0

The area is 21cm squared. u would have to find the length of the bottom triangle which is 14. than multiply that by the height which is 3. finally divide that all by 2 and youll get the area

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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

Can someone give me the pattern rule for 2 6 4 12 10 30 28 and wit are the next three numbers

Usimov [2.4K]

Multiply the first digit by 3 then subtract the answer by 2. Rule: x 3 - 2

5 0

3 years ago

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What probability statement would you add to P(blue) = 1 10 to make a complete probability model for the event choosing a foam b

algol [13]

Answer:

The chances of landing on blue are 1 in 4, or one fourth. The chances of landing on red are 1 in 4, or one fourth. This problem asked us to find some probabilities involving a spinner.

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3 years ago

Expanded form.2(b + c) *

11Alexandr11 [23.1K]

Answer:

Step-by-step explanation:

2b + 2c

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3 years ago

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find to consecutivephone number such that five times the smaller number plus 3 times the greater number make 59 hint let the num

Scorpion4ik [409]

Answer:

x = 7 is the answer for the smaller number

7 + 1 = 8 is the answer for the larger number

Step-by-step explanation:

LET x and x+1 be the two numbers here, as your hint suggests.

5x + 3(x+1) = 59

5x + 3x+3 = 59

8x = 59-3

8x = 56

/8 /8

--------------------------

x = 56/8 ---> x = 7

x = 7 is the answer for the smaller number

7 + 1 = 8 is the answer for the larger number

Check:

5 * 7 + 3 * 8 = 59

35 + 24 = 59

59 = 59 CORRECT

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3 years ago