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3 years ago

Three times the sum of a number and 4 is the same as 18 more than the number

1 answer:

5 0

First, figure out what you do and don't know....
You do know that 3 times the sum of a number and 4 is 18 more than the number....you don't know the number so you make it the variable x
now take 3 times the sum of a number and 4 and make that an expression 3x+4 this expression is the same or equal to the sum of x and 18 x+18
3x+4=x+18
2x+4=18
2x=14
x=7
hope this helped :)

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Answer:

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Step-by-step explanation:

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Answer:

The 99% confidence interval estimate of the percentage of girls born is (0.8, 0.9).

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Step-by-step explanation:

In a sample with a number n of people surveyed with a probability of a success of $\pi$ , and a confidence interval $1-\alpha$ , we have the following confidence interval of proportions.

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In which

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For this problem, we have that:

In the study 340 babies were born, and 289 of them were girls. This means that $n = 340, \pi = \frac{289}{340} = 0.85$

Use the sample data to construct a 99% confidence interval estimate of the percentage of girls born.

So $\alpha = 0.01$ , z is the value of Z that has a pvalue of $1 - \frac{0.01}{2} = 0.995$ , so $z = 2.575$ .

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The upper limit of this interval is:

$\pi + z\sqrt{\frac{\pi(1-\pi)}{340}} = 0.85 + 2.575\sqrt{\frac{0.85*0.15}{400}} = 0.90$

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3 years ago

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Lady bird [3.3K]

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3 years ago

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LenaWriter [7]

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