Extend the rate table to find the unknown value in the

The U.S. Census Bureau conducts a study to determine the time needed to complete the short form. The Bureau surveys 200 people.

NISA [10]

Answer:

$8.2-2.58\frac{2.2}{\sqrt{18}}=6.86$

$8.2+2.58\frac{2.2}{\sqrt{18}}=9.54$

So on this case the 90% confidence interval would be given by (6.86;9.54) And the error is given by:

$ME= 2.58\frac{2.2}{\sqrt{18}} =1.338$

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".

$\bar X=8.2$ represent the sample mean for the sample

$\mu$ population mean (variable of interest)

$\sigma=2.2$ 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)

Since the Confidence is 0.90 or 90%, the value of $\alpha=0.1$ and $\alpha/2 =0.005$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-NORM.INV(0.005,0,1)".And we see that $z_{\alpha/2}=2.58$

Now we have everything in order to replace into formula (1):

$8.2-2.58\frac{2.2}{\sqrt{18}}=6.86$

$8.2+2.58\frac{2.2}{\sqrt{18}}=9.54$

So on this case the 90% confidence interval would be given by (6.86;9.54) And the error is given by:

$ME= 2.58\frac{2.2}{\sqrt{18}} =1.338$

8 0

2 years ago

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Help pleaseeee!!! i’ll give brainly

Aloiza [94]

1,13
2,26
3,39
4,52
5,65

6 0

2 years ago

A coat regularly cost $125 is put on sale for $75

Stels [109]

If a coat is regularly $125, and they mark it down to $75, we could figure out how much money was taken off by subtracting $75, from $125

$125 - $75 = $50

So the coats price was cut by $50.

Hope it helps
Please mark brainliest!

7 0

2 years ago

1. I mark as brainliest

ludmilkaskok [199]

Answer:

d

Step-by-step explanation:

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2 years ago

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A mixture of 17 %disinfectant solution is to be made from 10% and 20% disinfectant solution. How much of each solution should be

8090 [49]

Since 20 total gallons are needed, the amount of 10% solutions can be x and the amount of 20% solutions can be (20-x) since they add up to 20. In addition, the 17% solution has 20 gallons. Putting this into an equation, we get that 10% is 0.1 (by moving the decimal 2 spots to the left) , 0.2=20%, and 0.17=17%. With that information, we can determine that 10%*x+20%*(20-x)=20*0.17 due to that with 20 gallons of the 27% solution, we need a certain amount of solution. For every gallon, we add 0.17 of the solution, so we have 20*0.17. Similarly, we want that total amount to be represented by the amount of 20% + the amount of 10%.

0.1x+0.2(20-x)=0.1x+4-0.2x=-0.1x+4 using the distributive property
-0.1x+4=20*0.17=3.4. Subtract 4 from both sides to get -0.1x=-0.6, and multiply both sides by -10 (to separate x) to get x=6. Therefore, the amount of 10% solution is 6 gallons and the amount of 20% solution is 20-5=14 gallons

3 0

3 years ago