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3 years ago

Need help with us question

Mathematics

1 answer:

lina2011 [118]3 years ago

7 0

Answer:

17. 20

18. 50

19. 50

20. 70

21. 110

22. 160

Step-by-step explanation:

I did this assignment already :)

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“At a restaurant the cost for a breakfast taco and a small glass of milk is $2.10. The cost for 2 tacos and 3 small glasses of m

gregori [183]

Answer:

t+m=2.10 -----------equation 1

2t+3m=5.15----------equation 2

Comment on my answer if you want me to show you how to use them to solve. but what I gave above is what the question asked

Step-by-step explanation:

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3 years ago

Identify two ordered pairs below that would form a direct variation:

Aleks [24]

Answer:

(12,3) and (20,5)

Step-by-step explanation:

When using the direct variation equation we can check these by division and we get .25 for the answer of both.

3/12 and 5/20

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3 years ago

The National Institute of Standards and Technology (NIST) supplies "standard materials" whose physical properties are supposed t

Lady bird [3.3K]

Answer:

$10.08-1.64\frac{0.1}{\sqrt{6}}=10.013$

$10.08+1.64\frac{0.1}{\sqrt{6}}=10.147$

So on this case the 90% confidence interval would be given by (10.013;10.147)

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.

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".

$\bar X$ represent the sample mean for the sample

$\mu$ population mean (variable of interest)

$\sigma =0.1$ represent the population standard deviation

n represent the sample size

Solution to the problem

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

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

In order to calculate the mean and the sample deviation we can use the following formulas:

$\bar X= \sum_{i=1}^n \frac{x_i}{n}$ (2)

$s=\sqrt{\frac{\sum_{i=1}^n (x_i-\bar X)}{n-1}}$ (3)

The mean calculated for this case is $\bar X=10.08$

Since the Confidence is 0.90 or 90%, the value of $\alpha=0.1$ and $\alpha/2 =0.05$ , and we can use excel, a calculator or a tabel to find the critical value. The excel command would be: "=-NORM.INV(0.05,0,1)".And we see that $z_{\alpha/2}=1.64$