I need help please :(

Mathematics

1 answer:

Anuta_ua [19.1K]3 years ago

5 0

15x + 11x + 8x+5 = 180

34x + 5 = 180

34x = 180-5

34x = 175

x = 5.147

by substitution each value by of x by 5

75 + 55 + 45 = 175

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Step-by-step explanation:

Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

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$\bar X=150000$ represent the sample mean

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s=15000 represent the sample standard deviation

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Solution to the problem

The confidence interval for the mean is given by the following formula:

$\bar X \pm t_{\alpha/2}\frac{s}{\sqrt{n}}$ (1)

In order to calculate the critical value $t_{\alpha/2}$ we need to find first the degrees of freedom, given by:

$df=n-1=35-1=34$

Since the Confidence is 0.95 or 95%, the value of $\alpha=0.05$ and $\alpha/2 =0.025$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.025,34)".And we see that $t_{\alpha/2}=2.032$