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4 years ago

4(5n -7) =10+2 i need step by step explanation i dont get it

Mathematics

1 answer:

ser-zykov [4K]4 years ago

7 0

Answer:

n=2

Step-by-step explanation:

4(5n-7)=10+2

1) First, distribute (multiply out 4)

20n-28=10+2

2) Combine like terms (add 10 and 2)

20n-28=12

3) Isolate the variable (Add 28 to 12)

20n=40

4) Isolate the variable (Divide by 20)

n=2

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Step-by-step explanation:

Previous concepts

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".

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$X \sim N(\mu=100,\sigma=6)$

And let $\bar X$ represent the sample mean, by the central limit theorem, the distribution for the sample mean is given by:

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$\bar X \sim N(100,\frac{6}{\sqrt{25}}=1.2)$

$\mu_{\bar X}=100$ $\sigma^2_{\bar X}=1.2^2=1.44$

b. What is the probability that x overbarxgreater than>101

First we can to find the z score for the value of 101. And in order to do this we need to apply the formula for the z score given by:

$z=\frac{x-\mu}{\frac{\sigma}{\sqrt{n}}}$

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On this last step we use the complement rule.

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First we can to find the z score for the value of 98.

$z=\frac{98-100}{\frac{6}{\sqrt{25}}}=-1.67$

And we want to find this probability:

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